TCI rubber sealing bearing tricone bit
tci(tungsten carbide insert). these tricones are designed for soft to very hard formations depending on the style and quantity of the carbides on the drill bit...because of its versatility and performance, it's still one of the main rock bits in use today. it is widely used for oil&gas, water well, geotechnical, environmental, geothermal, construction, exploration and mining drilling. 
1. soft formations(417, 437, 517, 537)
features large chisel-shaped inserts to provide the highest penetration rate in the softest formations such as shales, clays, limestone and sands. 
2. soft to medium formations(617, 637)
designed to drill effectively in formations such as hard limestone, dolomite, hard sands, and other formations with hard cherty. 
3. medium to hard formations(737)
for extremely hard formations such as chert, granite, flint, and taconite. features short, closely spaced inserts to ensure maximum penetration rate and wear resistance.