... High-quality hydraulic oil,smooth move 3.Max Door Weight :150kg 4.30,000 times test 5.Three years warranty Floor Spring ... safe application standards;2.Filled with high quality hydraulic oil;3.Built-in pressure ... in this line . Could supply the high quality with competitive prices . Warm welcome to ... contact with me! 150kg,Double speed ,high quality floor spring & door closer &door hinge;floor hinge ...