1.Clear floor design, save space. 2.Adopt double cylinder, 4x4 higher and stronger chain, the wire rope balance system. 3.Both sided manual release. 4.Rubber pad door-opening protection. 5.Rubber support pad adopts double helix adjustment height and height increase joint. 6.Limit switch. 7.The arm adopts two stages or three stages design, larger range adjustment, suitable for different vehicle chassis, three-node arm optional installation.