Built for heavy-duty precision, the SawStop Router Lift features a chain-synchronized four-post lifting system, positive lock, precision above-table elevation measurement and adjustments, and adaptive collars to fit multiple router sizes. 9.25" x 11.75" top plate fits perfectly into each SawStop Router Table. Maximum router diameter: 4 1/4". Minimum router diameter: 3 1/4". Phenolic insert ring diameter: 3 3/4". Router reducer collars (included): 3 1/4" & 3 1/2"