This door bar is not screwed between the doorposts because you can put it onto the door frame and than you can hang on it with your weight. After the training you can easily remove it again.
The door bar has different holding positions for Pull-ups.
But there´s also the possibility for using it as press-up bar, sit up bar or dip training.
The door bar can be put onto door frames with a width of 70 - 78 cm and a depth of 1 - 16 cm.