Tower Bolt 1. Material: 35k,q235, c1010 2. Surface: Black, ZP, HDG 3. Grade: 4.8,6.8,8.8 4. Standards: DIN933/931/7990 Tower Bolt1. Material: 35k,q235, c10102. Surface: Black, ZP, HDG3. Grade: 4.8,6.8,8.84. Standards: DIN933/931/960/961/5585. Minimum order: 1 ton Tower Bolt