This product is a Swiss FM711 amplifier board empty PCB board a pair of price some board parameters are as follows: 1 board model FM711 amplifier board empty board 2: board size: 250X 120mm 3 board: fiberglass board 4: all parameters are introduced below the empty board single piece size of the empty board: 250X120MM the empty board has printed all the device parameters. The enthusiasts who bought the device by themselves can enter the seat and then deliver the product, and will send a tutorial to the user.