Specially designed to change to 6" disc by screw on the special bolt to meet the balance. Self-generated vacuum only. Body is made from durable high strength material. Lower body with low center designed for operating steady with working face. Dustproof bearing to effectively lengthen bearing life. Free speed: 12000 rpm. Air pressure: 90psi. Orbit dia.: 5mm. Air inlet: 1/4". Pad dia.: 5"(6 hole); Weight: 0.9kg. Vacuum adapter size : 1", 1-1/4".