Wormdrive, Rolling Carriage, Skateplate, Transforms Left Drive Circular Saw (Wormdrive) Into A Precision Cutting Tool, Two Durable Polyurethane Rollers With Delrin Bearings Put Saw On A Rolling Track Ensuring Minimal Friction During The Cutting Process, Making Straight & Smooth Cutting Easy, While Increasing Cut Efficiency, Highly Durable Glass Filled Nylon, Fits A Wide Range Of Corded, Left Drive 7-1/4" Circular Saw Brands,Installation & Removal Skateplate Takes Minutes, Reduced Chance Of Kickbacks, Less Strain & Fatigue, Nominal Amount Of Cut Depth Loss, Includes Skateplate & Skateguide.