THIS IS A TWO PACK OF THESE BOARDS. The Epic UMC V4 Universal Mining Control Board and Firmware is designed specifically for Antminer S19/S21 miners, utilizing the SHA-256d hash algorithm for Bitcoin mining. This control board allows users to easily manage and optimize their mining rigs, maximizing efficiency and profitability. With its compatibility with ASIC mining hardware, this product offers a comprehensive solution for mining enthusiasts looking to enhance their mining operations. Upgrade your mining setup with the Epic UMC V4 for enhanced performance and control.