The Bosch HC4022 drill bit features a **spline shank**, not a "gear" The "spline" refers to the shape of the shank, which has 12 grooves or " teeth" designed to securely fit into a spline-drive rotary hammer. This interface ensures efficient energy transfer and prevents slipping when drilling into heavy-duty materials like concrete or stone. It is not compatible with standard SDS-Plus or SDS-Max chucks.