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WhatsMiner M66S 300 TH/s – 18W/T Professional Bitcoin Miner

WhatsMiner M66S delivers 296–300 TH/s with 18W/T efficiency. A dependable SHA-256 ASIC miner built for professional Bitcoin mining environments.

Key specifications

Hashrate
296T / 298T / 300T
Power draw
5,328–5,400 W (computed — 296T / 298T / 300T × 18 J/TH, the same hashrate × efficiency arithmetic MicroBT uses for its own "power on wall" figure. The 18W/T row below is efficiency, not connected load.)
Efficiency
18W/T (18J/TH)
Input voltage
AC 380–480 V, three-phase + ground — MicroBT’s own specification for this model, with a custom power cable of at least 16 A. No single-phase 200–240 V circuit runs this machine at any breaker size.
Cooling
Hydro (liquid) cooling — this unit must be plumbed into a coolant loop. MicroBT publishes no air-cooled variant of this model. It will not run on air, and the loop, CDU/dry cooler and coolant are not included with the miner.
Algorithm
SHA-256
Full specification table

Buying from ING Mining

  • PriceQuoted, not listedWe price this on condition, quantity and freight to your address. Call or email for current price and availability.
  • FreightQuoted with the unitFreight to your address is confirmed with the price, before you pay — multi-unit and pallet orders included.
  • ConditionNewAs described on this listing.
  • GradingGraded before listingThis unit’s own grade is in the description above — where a listing states none, it says so. The six-step bench procedure behind a grade is published in full.
  • WarrantyStated per unit, not per storeAny term for this machine is in the description above. Ask for the return terms on this exact unit before you pay — full terms are in the Shipping & buying tab below.
Get a price+1 (781) 577-0377ns@ingmining.comwho we are

Sold by ING Mining LLC — ING MINING® is a registered U.S. trademark.

Price:

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  • Condition graded per unit: new, tested working, refurbished or as-is
  • Warranty and returns stated per unit, not per store
  • Ships UPS Ground within 7 business days

Description

WhatsMiner M66S 300 TH/s – Reliable 18W/T SHA-256 Bitcoin Miner

The WhatsMiner M66S 300 TH/s is a professional-grade Bitcoin mining machine designed to deliver stable output with controlled energy consumption. Supporting hashrate configurations from 296 TH/s to 300 TH/s, this miner offers a balanced solution for operations that value consistency and efficiency. Manufactured by MicroBT, the WhatsMiner M66S 300 TH/s focuses on dependable long-term performance. In particular, its internal structure supports continuous operation, while temperature is held stable by the coolant loop this hydro unit has to be plumbed into — not by fans moving room air. Consequently, miners can operate this unit in demanding environments with confidence. For operators expanding their ASIC infrastructure, the ING Mining hardware selection includes a wide range of WhatsMiner models suitable for different facility sizes and power targets. Additionally, keeping track of network conditions is essential for informed mining decisions. Tools such as Bitcoin hashrate analytics provide insight into network activity and long-term performance trends.

Specifications

Model WhatsMiner M66S
Hashrate Options 296T / 298T / 300T
Power consumption 5,328–5,400 W (computed — 296T / 298T / 300T × 18 J/TH, the same hashrate × efficiency arithmetic MicroBT uses for its own "power on wall" figure. The 18W/T row below is efficiency, not connected load.)
Efficiency 18W/T (18J/TH)
Algorithm SHA-256
Coins mined Bitcoin (BTC), Bitcoin Cash (BCH)
Cooling Hydro (liquid) cooling — this unit must be plumbed into a coolant loop. MicroBT publishes no air-cooled variant of this model. It will not run on air, and the loop, CDU/dry cooler and coolant are not included with the miner.
Input voltage AC 380–480 V, three-phase + ground — MicroBT’s own specification for this model, with a custom power cable of at least 16 A. No single-phase 200–240 V circuit runs this machine at any breaker size.
Recommended Environment Mining farms, data centers, industrial mining facilities

Before you buy this one: it is a liquid-cooled machine on a three-phase supply. MicroBT rates the M66S at AC 380–480 V, three-phase with ground, and publishes it only as a hydro unit — around a litre of coolant per machine, plumbed into a loop with a CDU or dry cooler that you supply. That is two separate things a 240 V air-cooled farm does not have. It is the right machine for a container or a purpose-built hydro room and the wrong machine for a garage or a shed, whatever the breaker is rated at. If you are buying a lot of these and want to know what the loop and the service actually have to be before you commit, call +1 (781) 577-0377 or email ns@ingmining.com and we will go through it with you.

What’s in the box

  • 1 × WhatsMiner M66S
  • Nothing that is not listed above. Cords, controllers, brackets and spares are only included when this listing names them — if you need to know before you pay, ask on +1 (781) 577-0377 or ns@ingmining.com and we will confirm in writing what is physically in the crate

Overall, this offers dependable performance with predictable efficiency. Therefore, it is a practical option for professional miners who require stable output and proven MicroBT engineering in large-scale Bitcoin mining operations.

Questions buyers ask about this machine

Will this run on a normal household outlet?

No. This machine needs a three-phase AC 380–480 V supply — that is MicroBT’s own rating for it. A North American 120 V household outlet will not run it, and neither will a single-phase 240 V circuit at any breaker size, so there is no breaker calculation to do here: it is a three-phase machine or it is nothing. It also has to be plumbed into a coolant loop before it will run at all. Have an electrician and whoever runs your cooling confirm both before the pallet arrives.

What can I mine with it?

It mines Bitcoin (BTC), Bitcoin Cash (BCH). The algorithm is SHA-256, and ASIC silicon is single-purpose: it will mine coins on that algorithm and nothing else, whatever the price of anything else does.

Is this a new unit?

Yes — new stock, as described in this listing. Any manufacturer warranty term that applies is stated in the description above; where none is stated, none is claimed.

Shipping cost for this exact item, and how warranty and returns work here, are answered in the Shipping & buying tab on this page. Anything else, ask a person on +1 (781) 577-0377 or ns@ingmining.com — we would rather talk before you buy.

Related hardware and where this sits in the store

Other WhatsMiner units to weigh against this one:

Categories: Bitcoin miner, New ASIC miners, Whatsminer BTC Miners and Hydro Cooling.




Where this listing sits

This one is on the new shelf. New stock, as described in the listing. Any manufacturer warranty term that applies is named in the description; where none is named, none is claimed.

What our grades mean

These are the only words we use, and each one means a specific thing. They are not interchangeable and we do not soften them to move stock.

NewUnused stock. Factory sealed unless the listing says otherwise — “new, open box” means exactly that, and the listing will say it.
Tested workingSecond-hand, and it ran on our bench at the hashrate the listing states. We measured it; we are not repeating what the last owner told us. Expect cosmetic wear.
RefurbishedTested working, plus work done: cleaned, thermal paste and fans dealt with, failed components replaced. The listing says what was actually done to that unit rather than using the word as decoration.
As-is / for partsSold with no working claim at all, at a price that reflects it. Buy these to repair or to harvest. If a listing says as-is, assume it does not hash until you have proved otherwise.
UntestedWe have it, we have not powered it, and we are not going to pretend we did. Rarer than as-is and always stated explicitly.

What a grade here does not mean

  • Cosmetic wear is not a fault. Dust, scratches, scuffed labels and discoloured plastics are normal on hardware that has been earning. We photograph what we have; if the pictures matter to you, ask for more and we will take them.
  • A grade is not a warranty. Warranty terms are stated per listing, never per store — see the Shipping & buying tab. A tested-working grade describes what the machine did on our bench, not what we owe you in six months.
  • A boosted hashrate is not a spec. Where a unit ships on tuned firmware we say so and we give the factory figures too, because overclocking raises power faster than it raises hashrate — a tuned machine is less efficient per terahash than stock, not more.
  • We will not invent a grade to fill a field. If a unit came in without history and has not been through the bench, its listing says that.

How the grade gets decided

A used-hardware seller who will not tell you how they test is asking you to take the grade on trust. Ours is published: the six-step bench procedure every machine goes through, and the five measurements that get recorded — per-board hashrate, chip count, measured wall power rather than the nameplate figure, hardware error rate, and temperature under sustained load. When it reaches you, run the 48-hour acceptance test straight away, while the freight claim window is still open.

Buying second-hand for the first time? How to buy a used ASIC miner without getting burned is the long version, written from the repair bench rather than from a spec sheet.

Shipping

This listing is quoted rather than priced, and freight is quoted with it. Tell us where it is going and we will confirm the shipping cost to that address with the price, before you pay — on a multi-unit or pallet order that is the only honest way to do it.

Outside the United States the checkout quotes a flat international rate. On multi-unit or pallet orders, contact us before ordering so freight to your destination can be confirmed properly. What to check when the pallet arrives, and how a freight claim works, is covered in the mining hardware shipping guide.

What to do the day it arrives

Photograph the pallet or the box before you open it, and keep the packaging until you are satisfied. Freight claim windows are short, and damage found on day two is a conversation while damage found on day thirty is an argument.

Then run the 48-hour acceptance test straight away, while that window is still open. It is the same ground our own bench covers, so you can compare like for like: how the grade on this listing was arrived at, and the five measurements we record, are set out in the Condition & grading tab on this page.

Condition, warranty and returns

Condition: New — as described on this listing.

Warranty is stated per listing, not across the catalogue. Some units carry a manufacturer term and say so above, naming the term and the date it runs from. Many units, particularly used and AS-IS stock, carry none, and those listings do not claim one. There is no blanket warranty covering a catalogue that runs from sealed factory stock to a hashboard sold for parts. For what a mining warranty normally covers, see ASIC miner warranty explained.

Returns: ask for the terms on this unit before you pay. No single returns window is published for the whole store, because the sensible terms on a tested working machine and on a board sold AS-IS for parts are not the same terms. Email or call and ask what applies to this exact item — it is a two-minute conversation and a great deal cheaper than a dispute.

Where you are going to run it

Two questions decide whether a machine like this works where you live, and neither of them is about the miner: can the circuit carry it, and what does your electricity cost? Most full-size machines here want a dedicated 240 V circuit and run at 70–75 dB continuously. A few do not — the Avalon Q publishes 45–65 dB and runs on 110–240 V — so read the voltage and noise figures on this listing rather than assuming. ASIC miner power requirements covers breaker sizing and what the install actually involves; cooling covers where the heat and the noise end up.

If your power is not genuinely cheap, hosting is the question to be asking instead of which miner to buy. Break-even electricity rate is hashprice divided by (24 × J/TH), and hashrate cancels out of it entirely — which is why a cheap old machine on expensive power loses money faster than an expensive new one does. The buying guide has the arithmetic; work out your own number before you buy anything.

If hosting is the answer, get written answers on three things before you sign: who pays for repairs, what the uptime commitment actually pays out when it is missed, and how curtailment is handled. A flat per-machine monthly rate is where most of the unpleasant surprises live. Types of mining farm compares the models and hosting versus cloud mining covers why owning the hardware is the better end of that trade. Ask us before you commit — it is a five-minute call and a great deal cheaper than a contract you cannot get out of.

What we do once it is racked, wherever that is. Deployment, firmware and monitoring are a service we run rather than a line on a page: pool and network setup, Braiins OS or VNish tuning, offline alerts, and board-level fault-finding when a machine stops hashing — ASIC mining consulting sets out what that covers. The hosting agreement itself is between you and the facility. What we can give you is the number most hosting disputes turn on: what this machine measured at the wall on our bench, so a shortfall on site is a figure to compare against rather than an argument about what it should have been doing.

Who you are buying from

ING Mining LLC, Hanson, Massachusetts. ING MINING® is a registered U.S. trademark; our marketplace feedback is on the reviews page and the longer version of who we are is on about. Reach a person on +1 (781) 577-0377 or ns@ingmining.com.

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