Internal Serrated Tooth Lock Washer A4 (316) M3

This A4 (316) marine-grade stainless steel internal serrated tooth lock washer bites into the underside of a bolt head or nut to resist loosening under vibration, covering M3 to M12.

The internal serrations sit inside the washer's outside diameter, so it locks the joint without extending past the fastener's footprint.

At a glance

• Vibration-prone fixings — resists loosening on machinery, vehicles and equipment
• Low-profile joints — fits neatly under a bolt head or nut without extending past the outside diameter
• Marine and outdoor fixings — stainless steel resists corrosion

Full specifications, applications and features are in the tabs below.