Polyurethane UN 40*50*6 40x50x6 45*55*6 45x55x6 U Cup Lip Cylinder Piston Hydraulic Rotary Shaft Rod Ring Gasket Wiper Oil Seal polyurethane un 14 22 5 14x22x5 14 25 5 14x24x5 u cup lip cylinder piston hydraulic rotary shaft rod ring gasket wiper oil seal