We supply drilling rigs and its parts. The model come with zj20dbs, zj30dbs, zj40dbs, zj50dbs, zj70dbs. The available tools are tricone rock bits:tci & steel tooth bits 3 7/8" - 36", pdc bits matrix body & steel body 3 1/8" - 17 1/2", drag bits 3-wing & 4-wing step type & chevronmore...