the bump on the bottom of this tub that be suppose to prevent the baby from slip down -lrb- he leg straddle it -rrb- , not only do NOT in fact prevent slippage in the least , but once baby slip , he back be now roll over this hard plastic bump ! although baby do not complain , it be hard for I to hold he in place so that he do not slip down . Wish the bump be much higher or not there at all . not a good purchase .