Handles door weights up to 40 kg - pair of door closers (up to 20 kg - 1 door closer). A door closer should be mounted in the middle of the door (if only one door closer is to be mounted); (B). The door and door frame should be kept in a horizontal plane and the drop should not exceed 3 mm. Adjustable tension - Adjust the closing force of the door. To use this product, there must be a door frame, and the width of the door frame must be more than 3 cm. Easy to assemble and comes with all necessary fasteners. Comes with 2 door closers. Suitable for various types of doors 2-piece automatic door closer, silent spring door closer, tension adjustable It is spring-loaded with adjustable tension and can be used on left or right opening doors up to 40 kg. Features: Reduce buffering speed, protect doors to close the door, more convenient Reduce noise when closing the door IMPORTANT: 1. Adjustable tension - adjust the closing force of the door - insert the Allen key and turn clockwise or counter-clockwise. 2. A door closer should be mounted in the middle of the door (if only one door closer is to be mounted) 3. The door and door frame should be kept in a horizontal plane and the drop should not exceed 3 mm. 4. If you want to use this product, there must be a door frame, and the width of the door frame must be more than 3 cm. 5. If the door is heavy (weight ≤ 40 kg), you must install two door closers, the best installation position is one up and one down, so that the door can close normally. /p> What's included: 2 x door closers