... drill bits for quarrying, mining, construction 2. button bit, thread bit, dth bit, etc 3. export to over 40 countrie KAIYU, ... customers to choose, like taper bit(taper button bit, taper chisel bit and taper cross bit), thread bit( R thread and T thread), ... retrac bit and dth bit( from 3" to 8" are available Kaiyu Chisel bit ...