Espag handles are the most common type of window handle used today. A locking system with a flat metal strip which runs up the side that locks into the frame. The locking mechanism moves when the window handle is turned. They fix onto the window with two fixing screws and have a square spindle bar which protrudes from the base. This spindle slots into the lock and then operates a lock located inside the window . Approximately 90% of Espag handles have a standard fixing size, with two screws which are 43mm apart. You can usually interchange Espag handles with any other type, without having to make any adjustments.One thing to be aware of is that they also have various spindle lengths depending on the window in question, and can be a short as 10mm or as long as 60mm.Most of handles come with a 50mm spindle length as standard and this can then be cut down to suit with a normal hacksaw if necessary.