1.Bolt grade from 4.8 to 8.8 2.Quality is ... ,pipline and other fields Description: Material:carbon steel or stainless steel.Assemble:bolt,nut,washer,water-proof plastic ring,cone-shaped nut ... . Coating: Cr6 zinc/Cr3 zinc,3-5micron,WZP of YZP. Bolt:grade 4.8,5.8,6.8,8.8 are ...