standards: GB/DIN/JIS and NON-STANDARD Material: 65Mn/50CRV4/C67/SK5 Surface treatement ... bolts, U bolts, masonry bolts, roofing bolts.Nuts: spring nuts, T nuts, K nuts, rivet nuts, cage ... cap nuts.Washers: flat washers, spring washers, lock washers, structural Washers. square washer, bowl washer.Screws: machine screws, self tapping ... TransportationThe Best Choice for You disc spring washer DIN2093