Belltec Bullet Tooth Augers dig anything from dirt, clay, concrete, shale, limestone, coleci, and solid rock. Heavy duty cast iron head with replaceable carbide teeth set in tooth pockets, double flighting with hardfacing are featured. Best used with Belltec Diggers on skid steers, backhoes, mini-excavators and excavators. Slow, high-torque, heavy down pressure is the key to digging rock. Hard rock drilling REQUIRES maximum down pressure and maximum torque. Buy the heaviest-duty auger you can afford. Replacement teeth are inexpensive but not commonly needed. Belltec Augers are standard in four foot lengths standard to 36″, Custom sizes and continual flighting extra length models available. Standard with 2″ square couplers.