The Multi-joint™ spacing system allows you to make 1/4", 3/8" and 1/2" box joints as well as rabbet, dado, spline and sliding dovetail joints (for drawer glides) to any width with no limitation. Brass set-up bars (included) make setting up the Multi-joint very simple. Made from durable laminated MDF with UHMW guide bars for smooth operation. Platform measures 24" long which will fit across most router tables. Use your own bits or purchase one of ours. Please Note: This systemis designed to be used on table mounted routers only. Router bits not included.