Rockler Router Lift: Raise your router insert plate fast with the Quick-Gear, then down-shift to the precision gear for fine adjustments—Snap-Lock insert ring for easy bit changes. For Rockler or Bench Dog professional router tables, Pro router lift plate, which has an 8-1/4'' x 11-3/4'' plate. --- Router Insert Plate With Lift Features: 2018 Wood Magazine Innov8 Award winner – This router table plate makes height adjustments 4 times faster with the Quick-Gear 4-to-1 gear box ratio—dramatically speeds up your bit changes - Use the precision gear to make adjustments to within 0.001''—one hex wrench for both gears - Push the button to release the insert ring for fast bit changes—no tools to search for; no screws to lose - Two expansion bars beneath the adjustable router plate for a perfect friction fit with the router table rockler - Indexed marks on the fine adjustment screw let you raise the bit by a specific increment with the naked eye - Anti-backlash mechanism keeps the router from creeping downward—lock knob provides further insurance when running very large jobs - 3/8'' thick machined aluminum router plate insert and heavy-duty steel constructed guide posts with bronze bushings—designed for demanding daily use - Includes one insert ring with a 1-1/2'' opening; additional inserts (e.g. #55415) and zero-clearance insert (#53878) sold separately. --- The Pro Lift accepts router motors with a 4.2'' diameter (13.85'' circumference). Examples include the Porter-Cable 7518 and 7519. --- Router Table Accessory Tech Specifications: Compatible Motor Diameter: 4.2'' (13.19'' circumference); e.g. Porter-Cable 7518 - Plate Dimensions: 3/8'' thick (width varies; see product titles) - Insert Ring Inside Diameter: 1-1/2'' - Vertical Travel: ~5-1/2'' (varies w/ installation) - Quick-Gear Adjustment Rate: 1 revolution = 1/2'' - Precision Gear Adjustment Rate: 1 revolution = 1/8''.