1.The automatic start and stop device can be controlled through the vacuum cleaner,which provideds good controllability. 2.Power start switch with light display. 3.Automatic and manual switches are easy to switch 4.Rotary knob may adjust rotating speed to control suction through manual device,so as to coordinate the use of manual sa nder device. 5.Industrial-level high-density filter element increases the service life of moto 6.The paper bag is easy for removing dust and can prevent secondary pollution 7.The device has strong suction which reduces enviromental pollution,increase work efficiency,and improves painting quality. 8.The device has strong suction which reduces environmental pollution,increase work efficiency,and improves painting quality. 9.The device is equipped with two dust legs which allow the synchronous operation of two sets of sanders