The Hillman #10 Internal Lock Washer is a set of 24 internal lock washers designed to provide a secure fastening in applications where vibration or movement may cause regular washers to loosen. These lock washers have internal teeth that grip the screw or bolt and the mating surface, preventing loosening over time. They are typically used with #10 size screws or bolts and are ideal for various mechanical and construction applications where maintaining tight connections is critical.