The X-Beam's wider, super-strong crossbeam design increases the wrench's contact area with your hand by 500% over traditional wrenches - you can grasp the wider side of the wrench beam for more power and control with less stress on your hand. Open-end features Surface Drive Plus with reduced fastener rounding and up to 25% more torque. Ratcheting box end needs as little as 5deg to move fastener (vs. 30deg for standard box-end wrenches). Ratchet Head: Yes, Combination Type: Open + Boxed, Pieces (qty.): 12, Metric Size(s) (mm): 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19