Ratchet wrenches combined Eight pieces are available: 8 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 17 mm, and 19 mm; three ratchet adapters that convert the ratchet key into a ratchet trainer; one adapter with a 1/4" ratchet to use screwdriver heads; and 1/4", 3/8", 1/2"