Material: Aluminum alloy body + nickel-plated steel parts; The support is replaced by a nickelized surface metal support, easy to install and maintain, long service life. Suitable for the house, office, door of the hotel room.Wear of the door 25 ~ 45kg, door width 1000 mm, opening angle of the door up to 170 . The difference in height between the door frame and the door must be less than 5 cm, If the door frame is too high, you must use a material to lift the support so that it is parallel to the door frame. For best results, please make sure the door. Can open and close naturally and there is no excessive resistance. The spring voltage can be adjusted in a certain range. Aille: 1 piece Specifications: Material: Aluminum alloy body + nickel plane parts Size: 20 22 cm Package Contents: 1 Auto Close-door 5 Galvanized screw 1 Metal support 1 hex key Note: Please allow errors of 0-1 cm due to manual measurement.