Espag (espagnolette) handles are most commonly fitted to modern uPVC outward opening windows.
They have a 7mm square bar that drives the espagnolette locking mechanism within the opening sash and is held to the mechanism by two machine screws.
These handles have an industry standard of 43mm between centres and are available in varying pin lengths (dependent on finish selected) with locking and non-locking versions and in a variety of finishes and colours.
Some outward opening windows, especially aluminium ones, have a tongue drive espag handle. The tongue can be reduced in length to suit various window systems.