we have 10years' experience with this product, DIN6797 (6798)/ GB861.1 (862.1, 861.2, 862.2) standard :DIN6797 (6798)/ GB861.1 (862.1, 861.2, 862.2)The main role is in his teeth, the teeth from the locking effect can be very effective role!!Port: FOB ningbo Packing: Carton/Pallet Payment Terms: T/T Delivery Time: 15 Min Order Quantity: 1000pcs Serrated lock washer