Product standard: gb tb/t2347-93, arema or astm, bs and uic, or other standard or drawing required by clients. Specification: diameter m20 m22, m24 and 3/8"to 1-1/8", without length limited. Grade: 8.8, 10.9, grade 2, grade 5 and grade 8. Protection: black, galvanised and hot dip galvanised. Wooden
