The Bitmain Antminer Control Board (S21 Imm. , S21 XP Imm.) optimized for air-cooled, this high-quality control board ensures uninterrupted mining, efficient cooling, and comes packaged separately with support. By purchasing a new control board instead of repairing and replacing control board parts yourself, you can greatly save operation and maintenance time and costs, and replacing the control board is faster and more convenient.