Single Pack Maintenance Use: This pack includes the control board for grinder repair, grinding tool replacement, or polishing tool upkeep, while install steps should follow the current tool layout Grinder Repair Board Role: This replacement control board is built for 21V brushless grinder upkeep, helping buyers identify a dedicated repair part instead of a loose general electronic board Speed Control: Variable control helps the grinder respond to different grinding or polishing tasks, giving maintenance users a flexible replacement option for routine service work 21V Power Direction: The board is positioned for 21V brushless grinder use with ERP stated power orientation up to 2000W, so buyers can review specification direction before ordering a replacement Board Assembly Format: Mounted electronic components and the practical board structure present a replacement assembly that is easier to review during grinder repair and part selection, Manufacturer: LIzogli