Antminer S21 Buy Checklist: Verification Before Payment

The common patterns are consistent: a price meaningfully below market, pressure to pay quickly, payment to a personal account or an unverified wallet, stock photographs instead of the actual unit, and a company name that cannot be traced to a registered entity. Any two of those together should end the conversation.

test reports, serials, invoices and crypto payment flow. Legitimate sellers will happily slow down, answer questions, issue an invoice and photograph serials on the machines you are buying. Reluctance to do any of that is the signal.

Confirm a registered legal entity and physical address. Call the listed phone number and speak to a person. Request an invoice issued before payment. Ask for photographs of the exact units with serials visible, plus a bench-test report showing hashrate and per-board temperatures. Request written warranty terms.

Then verify independently: search the company name alongside review terms, check how long the domain has existed, and look for a consistent operating history rather than a site that appeared last month.

Cryptocurrency payments are irreversible, which is exactly why the order of operations matters. Get the invoice first, confirm the wallet address through a second channel, and never send funds to an address supplied only in a chat message. We publish payment addresses with QR codes inside a confirmed order rather than in ad-hoc messages.

We also accept CashApp, Chime and direct bank transfer with manual review on larger orders. For a first purchase from any supplier, a smaller trial order is a cheap way to test the whole process before committing serious capital.

Large marketplaces host both legitimate resellers and opportunists. The structural problems are that warranty is often nominal, machines may ship without a PSU or with region-incompatible cords, firmware state is undisclosed, and customs documentation is frequently wrong — which turns a bargain into a delayed, taxed and unsupported machine.

If you do buy there, insist on the same verification checklist, use the platform's protections, and assume you are buying the hardware only, with no support attached to it.

A supplier who tells you not to buy something is worth more than one who sells you everything. Ours starts with your power rate and available amperage, models the options, and recommends the machine that actually fits — sometimes that means fewer units, sometimes hosting instead.

Every machine referenced here is listed on our catalogue with a live price, a bench-test report and a photograph of the actual unit, so you can move from this guide to a checkout in two clicks. Crypto, CashApp, Chime and bank transfer are all accepted, and orders ship worldwide from our Hong Kong warehouse to the USA, Canada, Europe, Asia, the Middle East, Latin America and Australia.

The failure mode in this market is almost never the hardware — it is the transaction. Insist on a named legal entity, a verifiable phone number, a written warranty term, an invoice issued before funds move, serial numbers photographed on the machines you are actually buying, and a test report showing hashrate and per-board temperatures from a real bench run.

Every machine referenced here is listed on our catalogue with a live price, a bench-test report and a photograph of the actual unit, so you can move from this guide to a checkout in two clicks. Crypto, CashApp, Chime and bank transfer are all accepted, and orders ship worldwide from our Hong Kong warehouse to the USA, Canada, Europe, Asia, the Middle East, Latin America and Australia.

We ship air freight via DHL and FedEx with full commercial invoices, HS codes and, where relevant, EORI and VAT documentation for EU and UK buyers. Typical door-to-door transit is three to seven business days to North America and Europe, with sea freight available for container-scale orders where the freight saving justifies the longer timeline.

Deployment support does not stop at delivery. Send us your panel schedule, ambient conditions and pool preference and we will return a circuit plan, a firmware recommendation and a monitoring configuration so the fleet earns from the first day rather than the second week.