This lock installation kit can open diameter 54mm and 22mm hole suitable for spherical lock Installation. It has excellent workmanship and wear-resistance which can be used for wood, plywood, plastic and other materials opening holes. SPECIFICATIONS: • Forstner Bit 2-1/8’’ (54mm) is for lockset hole • Forstner Bit 7/8’’ (22mm) is for latch hole • Suitable for wood, plywood & plastic