The Ullman Precision Product Hand Checkering Tool Doiron Type 4 is Ullman's most common cutter for deepening the diamonds and bringing them to point. It's 3/8" length is the optimal size for keeping straight lines and creating crisp diamonds over a majority of the pattern. It has a 20 degree ground on the front and rear of the cutter giving you a clear view. This helps to eliminate overruns as well. One push and one pull makes any checkering kit complete.