The scraper can be set in “float” mode or “rigid” mode. The scraper, as shipped, is set, by default, in rigid mode. To set in “float” mode pull the 2 clips from the silver pins on the rear of the frame. The top rear angle is pre-drilled for you to store these pins in when set in float mode. Float mode allows the unit to maintain level even though the tractor may be pitching up and down.