Fan Simulator for Antminer S21 T21 KS5

The Antminer S21 fan simulator is a device that tricks an ASIC miner into thinking its cooling fans are running at normal speed, enabling the use of more efficient cooling methods without triggering safety shutdowns or error messages. This speed controller is commonly used to upgrade the S21 air-cooled miner to a water-cooled system or to install a silencer. It is a 4-in-1 speed controller, and each S21 miner requires only one unit.