screw lift elevator 3004-01 1. special screw 30-04-01 2.other washers: spring washer, square washer, wave spring washer... special screw 30-04-01 Brand Nmae:WeifengStandard Model:DIN,AHSI,JIS,ASTM, Non-standardFinish:Black,Zinc plated,Hot galvanized, Cr Cu or Ni Plated Material:Carbon Steel,Brass, Stainless steel,Spring steel, Alloy steel..