Usage Tips:"Keep open at 90~180 door open range - When your opening angle is more than 90, this door closer can keep the door open at any angle. do not need to use external force or a stop door to keep the door open. If you like a well-ventilated room or need to move goods frequently, this will be your best choice. You just need to pull the door less than 90 and it will close automatically.High Quality & Adjustable Speed - The hydraulic door closer is made of aluminum alloy. It can automatically and silently close your door. Improve your quality of life. You no longer have to shout "close the door ". The door closer has 2 valves that independently control the closing and latching speed. You control the closing speed as you wish.Easy to install and standard of quality - The door closer comes with a detailed and clear installation manual and installation video. Simple and smooth installation. The hydraulic door closer has passed CE, UL, 3C certification and fire test. Manufactured according to European production standardsWidely Applicable: Size 2 door closer spring is used for 25-45kg doors and 750-850mm door width. Self-closing is suitable for right and left opening doors, wooden, metal, doors residential and commercial, exterior/interior door closer, fire door, hotel, condominium, apartment, warehouse."