Stegmeier MS009 1/2″ x 3 3/4″ x 7 1/4″ Slip-N-Join Couplers 12 per Case is a reusable forming material that is designed to provide excellent performance on radius forming projects. Slip-N-Join Lumber is light weight and easy to bend into a consistent radius. Slip-N-Join Lumber will not warp or swell from water absorption. Sections can be connected with included couplers.