We carries a full line of adapter subs designed to make the assembly of the complete system hassle free. We also offer blank end subs allowing you to customize your needs. Subs or adapters are used as connectors or coupling to connect drill rods, core barrels, casing, rock bits, water swivel, hoisting plug, fishing tools with the water swivels, hoist plugs, etc. that have different size or type of threads. And we make heat treat to the sub adapters thread same as drill rods.