Can hold door weights up to 40 kg - Pair of door closers (up to 20 kg - 1 door closer). (A) 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 must be kept in a horizontal plane and the drop must not exceed 3 mm. Adjustable tension - Adjust the door closing force - Insert the hex key and turn it clockwise or counterclockwise. If you want to use this product, there must be a door frame and the width of the door frame must be greater than 3 cm. Simple to install and supplied with all required fixings. Come with 2 door closers and hex keys and screws. Suitable for different types of doors.