Four-slot slotted round lock nut with four external slots for hook-spanner engagement. It is normally paired with a lock washer: after tightening, the washer tab is bent into a slot to provide an anti‑loosening function. The nut is intended for axial positioning of shafts and for locking the inner rings of rolling bearings.

Available materials: 45# carbon steel, A2 (304) and A4 (316) stainless steel. Surface finishes offered include black oxide, blue‑white zinc and yellow zinc. Common applications include gearboxes, machine spindles, rollers and construction machinery. Please confirm required sizes, standards and washer/spanner compatibility when specifying this part.