Keep the door open within the opening range of 90-180 - When your door opening angle exceeds 90, this door closer can keep the door open at any angle .You dont need to use external force or stop door handle to hold the door open. This is your best option if you like a well-ventilated room or have to move a lot of loads. Just pull the door less than 90 and it closes automatically. HIGH QUALITY AND ADJUSTABLE SPEED - The hydraulic door closer is made of high quality aluminum alloy. It can automatically close your door silently. Will improve your quality of life. You dont have to yell close up anymore the door. The door closer has 2 valves that independently control the closing and latching speed. You can control the closing speed according to your needs. Widely Applicable - Size 3 door closer spring for door weight 35-40kg and door width 830-950mm. Self-closing is suitable for left and right doors, wooden doors, metal doors, doors residential and commercial, exterior/interior door closers, fire doors, hotels, apartments, apartment buildings, warehouses.