Armeg Interchangeable Switch-Blade is compatible for use with Armeg VDE screwdriver handle, VDE T-handle and VDE torque screwdriver. The versatile wide range, which includes 23 different blade sizes, has been designed to cover the most popular screw heads giving users a flexible system for use on the majority of live installation applications. All blades feature a 1/4″ hexagon drive combined with a precisely manufactured recess design, which when inserted into a Switch-Blade Handle provides blade auto-lock and retention, meaning the blades can simply click into the handle and be held securely for safe working.