supply of 7 / 8 ( 22.2 mm ) dia zinc plated / galvanised lock bolts with collar ( part no. 2820 ) with grip range 1.25 to 1.5 inches. one set consisting of 1 no. lock bolt & 1 no. collar. the head of the lock bolts necessarily be marked with manufactures identification. the marking on collar should be done on lower bottom surface rdso drg.wd-11036-s-01 alt.1 and wd-11036-s-02 alt. nil. spec: base metal- steel. astm b633 and astm b695 and astm b117 minimum 48 hrs. lock bolt should have a hardness in a range of 28-34 hrc and collar have a hardness in a range of 60-80hrc. [ warranty period: 30 months after the date of delivery ]