ALUMINUM SLEEVE NUT 1.ISO,ANSI,JIS,DIN,BS& non-standard fastener ... .Grade:4.8 ,6.8,8.8,9.8.......... ALUMINUM SLEEVE NUT,ALUMINUM WELD NUT,NUT A good non-standard fastenerS ... steel is SS201,202,302,304,316...copper is shiny brass , pure copper,such as H62,H65,H68...Aluminum is good ...