Looking at the shape, it seems to suggest that it sits in the bath and is "additional" to other handles.
The firs review says this:
"This is now a secondary hand grip for getting out of our deep bath, it supplements the one on our wall. stuck in on the edge of the bath. did not use it for a week to test out the suction capabilities to see if it moved, glad to say did not. Have now used it twice, it remains firmly in place. It has the three separate grips, top, bottom and side. all three good to help get you out of the bath."