Big Lift extra center support fits any full or queen size bed frame. The big lift insures rigid center support where you need it most. A Big Lift placed at the head and foot of your frame provides adequate support for our split box spring sets. Sturdy, all steel legs to give extra support. The Big Lift prevents your box spring from warping and mattress from sagging. The floor guides of this Big Lift have major adjustment space to fit most tall or short frames. The Big Lift is also necessary if you have hook in rails and are going to use a split box spring set.