ALUMINUM SLEEVE NUT 1.ISO,ANSI,JIS,DIN,BS& non-standard fastener ... ,6.8,8.8,9.8.......... ALUMINUM SLEEVE NUT,ALUMINUM WELD NUT,NUT A good non-standard fastenerS manufacturer for your better ... manufacturer with more than 20 years experiences in screw,bolt,nut,washer,rivet, stud, pin,wrench and so on .2 ... quality 1.The material are always use C1022 ,The percent C element is 0.18%-0.23% ,is higher hardness ...