Spring-loaded wheels turn one way and are adjustable for different material thickness. The unique design of the wheels keeps the material pressed firmly down and against the rip fence. Reduces chance of kickback. Wheels are made of a special composition that will not mar your work.Two wheels per set. Yellow. · Clockwise Rotation · Prevents kickback on tablesaws · Mounts to fences 3" to 3-1/2" high x 1" or wider · Non-Marring · Neoprene Wheels · Die-Cast Aluminum Construction · Great for router tables too!