Upgrade GRR-RIPPER 3D Pushblock to the advanced model. Includes 1 Stabilizing Plate and 1 Adjustable Spacer. The Stabilizing Plate provides 250% more stabilizing surface area. Like a featherboard, it keeps wood locked against the fence for a smooth cut - virtually eliminating binding. The Adjustable Spacer gives you 54 MicroJig GRR-RIPPER Upgrade Kit - GRAK-404