I have one of the dividers from PetSmart... Aaaand it's alright, as long as you don't use the metal clips. I did, and it let my girl in on the boy's side twice before I figured out that that was the problem. Also, putting little rocks on the bottom helps (I have glass "rocks" from the dollar store, but similar to these from PetSmart
). Honestly, though? I will probably never buy any more.