Loose link,the material is 40MnB,surface hardness is 52--58 HRC, They are for:1) Komatsu: PC60-5/6, PC100, PC200-1-3-5-6, PC300-3-5, PC400-3-5, PC400-3-5, D20, D30, D50, D60, D5D, D6D, D75, D80 (D85)2) Hitachi: EX100, EX200-1-2-3, EX300 3) Cat: E110B, E200B (E320), E240 (MS180), E300B, E330, SH200 4) Dawood: 220, UH07, UH08, SH300, HD250, HD400 (HD450), HD700 (HD770), HD820 (HD850), HD1220 ( ...