1S (Very Soft) -- Long, widely spaced teeth for softest formation (soft sediments, shales, clays, etc.)
  
1 (Soft) -- Reduced spacing between teeth for shale, soft limestone, loosely cemented sandstone, etc.
  
2M (Medium) -- More teeth and shorter teeth for hard shales, sandstones, limestones, etc.
  
3MT (Medium Hard) -- Short, closely spaced teeth for very hard rock (dolomite, limestone, very hard shales, etc.)
  
3T (Hard) -- Similar to "3MT" but teeth have "T" shape for slightly more abrasive formations.
  
3H (Very Hard) -- Features paired teeth on gage. High resistsance to abrasion from formations with high silica content.

Our roller rock milltooth tri-cone bits, are available in a variety of sizes and types which are listed below. To help you order the right bits, use the following guidelines to match the bit design to the formation you will be drilling.

We Carry the following sizes:

2 15/16", 3 1/4", 3 7/8", 4 1/8", 4 1/2", 5 7/8", 6", 6 1/4", 6 1/2", 6 3/4"