This board offers a pressure-filled experience for the receiver. To use, simply place the Cock and Balls through the larger hole in the back of the board. The cock can then be placed through the second hole to avoid any pressure to be placed on it. Use the two included screws/wing nuts to close the board. The board can be closed all the way down to 1" of space apart or as wide as 1. As the board is tightened, more and more pressure is applied to the balls. Both plates measure 7" in length 5" in width. Cock and Ball