The Gran Board U-shaped bracket is specifically designed for use with the Gran Board. This bracket stops the board from rotating and provides a stable hold. For use with the Gran Board only. When using the U-shaped bracket to hang a GRAN BOARD, please make sure to use M4 x 8mm COUNTERSUNK HEAD SCREWS. Do not to use TAP SCREWS on your Gran Board; otherwise, inner nuts are pushed inside the board, and this causes the malfunction of the sensor sheet.