A 21mm combination wrench, with an open end on one side and a box end on the other, both the same size. The open end slides onto a fastener from the side when there is no clearance to drop a wrench over the top of it; the box end wraps all the way around the head and is the end to lean on when the fastener is tight.

• Size: 21mm
• Open end and box end, both 21mm
• Metric size
• Box end for torque, open end for access