This part is CNC cut from 1/16" fiberglass reinforced G-10 stock, and is an exact replacement for the Upper Center Plate that comes in the Next Level 500mm and 650mm Hex Frame kits. This part is pre-drilled with two sets of mounting holes for most of the popular flight controller boards. The inner ring of holes have a 30.5mm square spacing for the OpenPilot CopterControl boards, and the outer ring of holes have a 45mm square spacing for boards such as the KK Copter, MultiWii, Hoverfly Sport, Paris and others.