AMM7996 Features: -Shear Gear and C-Clip. -Replacement for the ''fail safe'' gear which protects the cross feed gear box in the event of operator error during rotor machining. -Use with lathe models 4000 and 4100. -Shear Gear and C-Clip Replacement. Product Type: -Parts & Accessories. Use: -Brake Rotor. Quantity: -Single. Dimensions: Overall Height - Top to Bottom: -1 Inches. Overall Width - Side to Side: -3.8 Inches. Overall Depth - Front to Back: -4.7 Inches. Overall Product Weight: -0.05 Pounds.