1. For tube casings and couplings 2. Multi-tooth thread, 8API Round 3. Twin-lock 4.Good qualit and Good ... to oil and gas industry at home and abroad for many years. SMT carbide API threading inserts are ... buttress threads, 3,4,5,8,10 TPI available for cutting J55, L80, L80, and P110. Any special ... welcome. For more information, you are very welcome to contact us by phone and e-mail. Twin-lock Multi-tooth ...