supply of 5 / 8 inch ( 15.87mm ) dia zinc plated / galvanized lock bolt with collar, 5 / 8 inch ( 15.87mm ) dia zinc plated / galvanized lock bolt with collar ( part no. 2020 ) with grip range 3 1-38 mm. one set consisting of 01 nos lock bolt & one no. collar. base metal- steel, astm b633 & astm b695 & astm b117 minimum 48 hrs. lock bolt should have hardness in a range 28-34 hrc & collar have a hardness i n a range of 60-80 hrc. accepted: hardness of collar should be 60-80 hrb in place of 60-80 hrc, as per rds o drg. no. wd-11036-s-01, alt-1 & wd-11036-s-02, alt-nil or latest and confirming to spec. is / rdso-wd / 0001: 2022 of june 2022 or latest. [ warranty period: 30 months after the date of delivery ] => limited