Can hold door weights up to 40 kg - Pair of door closers (up to 20 kg - 1 door closer). A door closer must be installed in the middle of the door (if only one door closer is to be installed); (B). The door and door frame should be kept in a horizontal plane and the drop should not exceed 3MM. Adjustable tension - Adjust the closing force of the door If you wish to use this product there must be a door frame and the width of the door frame must be greater than 3cm. Simple to fit and supplied with all required fixings. Come with 2 door closers .Suitable for different kinds of doors 2-piece automatic door closers, silent spring door closers, adjustable tension It is spring-loaded with a adjustable tension and can be used on left or right opening doors up to 40 kg. Features: Reduce buffer speed, protect your doors Auto to close the door, more convenient Reduce the noise caused by closing the door IMPORTANT NOTICE: 1.. Adjustable tension - Adjust the door closing force - Insert the hex key and turn it clockwise or counterclockwise. 2. A door closer should be installed in the middle of the door (if only one door closer is to be installed) 3. The door and door frame should be kept in a horizontal plane, and the drop should not exceed 3MM. 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 3cm. 5. If it is a heavy duty door (weight 40 kg), you need to install two door closers, the best installation position is one up and down, so that the door can be closed normally. /p> What is included: 2 x door closers