An extension of the surface set bit concept, where the cutting elements are set in a single layer at the tool surface, the large size and greater exposure of thermally stable polycrystalline (TSP) diamond elements, results in very high penetration rates in suitable formations.

The exposure and the relative brittleness of TSP diamond, compared with a smaller natural stone or an array of synthetic crystals, results in vulnerability to breakage in hard ground, so these products are best suited to softer formations with any level of abrasiveness, where they are the most productive, long-lived tool available.

Premier TSP bits are designed to capitalise on the high potential rate of advance by paying particular attention to flushing, while providing a tough matrix to resist the most abrasive formations.