ZT330S Zephyr Tool 5/8” Microstop Countersink Cage are designed to provide precise and accurate depth control by limiting the travel of the cutter that’s in use, and aiding in the alignment of the cutter so that it is exactly perpendicular to the surface against which the cage rests. ZT330S Zephyr Tool 5/8” Microstop Countersink Cage are designed with hardened and ground spindles and are supported by bronze bushings for general use, or needle and ball bearings for more demanding applications. Thrust bearings provide axial support while the micro-adjustment offers the precise depth control. ZT330S Zephyr Tool 5/8” Microstop Countersink Cage offer a .001 depth adjustment.