From the Manufacturer, Gear wrench 85556 no.16 on box end x 1/2-Inch on open end XL spline ratcheting wrench.

Gear wrench XL spline ratcheting wrench has 20 Percent longer length for more leverage and spline design at wrench open and box ends for 25 Percent more strength at the point of pressure.

Ratcheting box-end needs as little as 5 degrees to move fastener vs 30 degrees for standard box end wrenches.

Surface drive plus provides stronger grip on fasteners, reduces fastener rounding and delivers up to 25 Percent more torque. Improved box end strength.