Q397 self-tapping clip nut Q312 leaf spring nut Q312 leaf spring nut (type B) YJT3034 clip nut automobile fender barbed clip tension spring nut SN421-683 elastic retainer cartridge nut for shaft Q673 QC/T621-1999 clamp IN25201 double stack self-locking washer DIN9250 Double-sided tooth lock washer JIS/B1216-2006 Bearing clamp DIN6798A/J internal and external serrated lock washer