Spreader Bar expands from 29 to 37 in. Three easy steps to assemble; instructions inside. Contains: one 14.5 in. center aluminum tube; two 14.5 in. spring locking expanding aluminum tubes; two cuffs. Spreader bar is made of aluminum. polypropylene. nickel-free metal D-rings. Cuffs made of polypropylene webbing. nickel-free metal hardware. Velcro. polyester binding. velboa fabric.