1) The frame made up of a mono-block steel plate has good strength and beautiful appearance.2) It is installed without foundation bolts, which is very convenient for installation and maintenance. 3) The surface of the roller, knurled and black coated, is antirust, wearable and has high strength and long service life. The attachment coefficient between tire and roller is not less than 0.9.4) It is lifted by gasbag, which has good synchronism and little failure. 5) It adopts ohm long sensor, which has high testing accuracy.
