ROADMASTER INVISIBRAKE HIDDEN BRAKE Permament Type; Electrical Operated; With Break Away System; With LED Monitor; 8-3/4 Inch Length x 8-3/4 Inch Width x 2-3/4 Inch Height; 12 Volt DC; 10.8 Amp Maximum Power Drawn; 2 Amp Battery Recharge Rate; 80 PSI Maximum Air Pressure