Usage Tips:Keep the door open between 90 and 180 - If your opening angle exceeds 90, this door closer can hold the door open at any angle. You don't need to use any external force or blockage to keep the door open. If you like a well-ventilated space or need to move loads frequently, this is your best option. Just pull the door back less than 90 to automatically close and adjustable speed - Hydraulic door is made of aluminium alloy. It will automatically close your door quietly. Improve your quality of life. You don't have to yell "shut the door" anymore. The door closer is equipped with 2 valves that independently control the closing and locking speed. You can control the stopping speed at will. Ease of Installation and Quality Standard - The closed door comes with a detailed and clear installation manual and installation video. It will be easy to install. Hydraulic doors are CE, UL, 3C certified and fire tested. Manufactured according to EU production standards" Widely used - Door closing spring No. 2 is used for doors weighing 25-45 kg and width 750-850 mm. Self-closing is suitable for left and right doors, wooden doors, metal doors, residential and commercial doors, Enclosed exterior/interior doors, fire doors, hotels, condos, apartment buildings and warehouses. Warranty: 3-year warranty, over 500,000 hydraulic door switches, you can rest assured.