B & H Panel Company Slats Mattress Supports - Strong Durable Powder Coated Steel! Made in the U.S.A with American Steel Bed frame/mattress support system One size fits Full, Queen, King, and California King Size beds. Each telescoping supports extend from 51" to 78" 5", 8", and 11" feet (3) each are included, hardware bag and instruction sheet. Center leg brckts, w/3-3/4" adj. glide, glide base is 1/2" x 2" round