Return Retreads are made of solid wood and used for remodeling an existing staircase. Available from 36 inches to 96 inches in length. The staircase must have at least one open stringer to utilize a return Retread. When standing at the base of your staircase looking up the staircase the side that has the open stringer is the side that requires a return end on the Retread. If both stringers are open you will require a double return Retread. This product will not cover dimensional lumber treads, a new riser will need to be attached to the existing riser of the staircase to hide the bottom of the existing dimensional lumber tread.