1. NO MARKS ON THE DOOR: The unique diamondshaped structure ensures your safety with its patented design. Nonslip PVC pads on both sides prevent the frame from breaking and avoid damage caused by sudden falls. The heavier the weight supported by the chin on the door, the more stable it becomes. 2. STURDY: The doormounted machine room is easy to install and fits most standardsized door frames. It can support up to 100 kg (250 lbs). 3. EASY INSTALLATION: Simply 'screw' each end until tight. You can install it on most standard doors or between two walls. Then, twist the middle of the bar to secure and tighten it. Mounting brackets and screws are included for a safe installation. 4. SPACESAVING MULTIFUNCTIONAL: With the overhead bar, you don't need to dedicate a special corner in the room—just a suitable door frame or two parallel walls. It can be adjusted to different heights on the pullup bar for various exercises.