Note the details:

TWO FAN SIMULATORS for the Bitmain Antminer Miners or any other Crypto-Miners with Pulse Wave Modulation (PWM) cooling fans (4-pin).

It works for all Antminers with PWM 4-pin Fans. Its chip artificially generates a 2200~6500 Fan RPM signal back to the miner's control board. It can work under 5~36V.

It is suggested to unplug the front fan and remove it from the miner so that it will not block the air flow into the miner. Plug the fan simulator into the front fan socket. The screen shot is the real world testing result.