Combines the speed of ratcheting with the access of the open end wrench. Open end ratcheting mechanism allows you to turn nuts and bolts without taking the wrench off the fastener. Dual Ratcheting. Ratcheting box-end needs as little as 5 degrees to move fastener. Surface drive reduces fastener rounding Sizes include: 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm and 19mm.