MALOUF Structures Adjustable Center Support System for Bed to Replace Wooden Bed Slats - Universal Size Adjusts from Full to King - Adjustable Leg Height Replaces wooden bed slats to create a stable sleep foundation - includes support rails only and is designed to attach to your existing bed frame Three adjustable-length steel cross rails and one heavy-duty support center rail for superior support Rails and center support adjust to fit Full, Full XL, Queen, King, and California King beds Leg height adjusts from 6.5 to 15.5 inches from floor to box spring Allen wrench included for leg height adjustment; 3-year U.S. warranty