Open end has specially designed grooves that direct wrench force away from fastener corners
Box opening design allows application of higher torque without rounding or deforming hex fastener points
No contact is made at the corners—instead, wrenching forces are placed on the flat surfaces behind the points
May be used on all common hex (6 point) fasteners with considerable advantage over conventional box end wrenches to increase both hand tool flexibility and economy
Box and open end openings are identical
Meets or exceeds aerospace specification AS 954 for 12 point fasteners (as defined by AS 870) to provide accurate torque/tension relationship for precision application
