Open end has specially designed grooves that direct wrench force away from fastner corners
Box opening design allows application of higher torque without rounding or deforming hex fastner corners. Instead, wrenching forces are placed on flat surfaces behind the points.
Meets or exceeds aerospace specification AS 954 for 12-point fastners (as defined by AS 870) to provide accurate torque/tensions relationship for precision application.
May be used on all common metric hex (6 point) fastners with considerable advantage over conventional box end wrenches to increase both hand tool flexibility and economy.
