Carbide bits have little blades (like microscopic razor blades) that cut at an angle. It actually shaves the acrylic, which means less pressure is required. This results in less dust, and since there's less friction there is less heat. Made of 100% tungsten carbide, which is the hardest material next to diamonds, carbide bits will last a long time. Use this bit for surface work, shortening acrylic product, and backfill cutting. The only difference between a large barrel and a small barrel bit is the circumference of the bit, allowing for nail techs to choose their preference.