Gimlets are a traditional, old world tool used to bore holes in wood without splitting. They are extremely useful when creating pilot holes for screws, especially in tight spaces. The tips are threaded with spiral cutting edges along the shafts. Once the threaded tip is started in the wood, the shaft is pulled deeper with no further pressure required. The cutting edges pare away the wood and pull the waste out through the entry hole. This is an 7 piece set made by the French firm Arno. Sizes ranging from 2 to 5 mm or roughly 1/16" to 3/16". They can be used for screws from #2 through #11. Tips are hardened. Black finish. Made in France.