Double open ended spanner is a tool used to provide grip and mechanical advantage in applying torque to turn objects-usually rotary fasteners, such as nuts and bolts-or keep them from turning. A twelves-pieces wrenches set with u-shap opening that grips two opposite faces of the bolt or nut. This wrenches are often double-ended, with a different-sized opening at each end. The ends are generally oriented at an angle of around 15 degrees to the longitudinal axis of the handle. This allows a greater range of movement in enclosed spaces by flipping the wrench over. Size:6x7,8x9,10x11,12x13,14x15,16x17,18x19,20x22,21x23,24x27,25x26 & 30x32mm