The Extension Adapter Pack contains a variety of extension adapters, which allow the use of Bosch’s power-change systems in holesaws made by such competitors as Starrett, Baco and Lenox. This pack contains two adapters for diameter 14-30 mm (1/2-inch-20UNF thread), and four adapters for diameter 32-210 mm (5/8-inch-18UNF thread).