The Leofoto FX3-XLR is an extension for the SONY FX3 XLR handle. There is a top rail to secure the extension in place with various accessory mounting holes. The rail uses two 3/8″ mounting screws to mount directly to the original top handle, while the extension uses one 3/8″ mounting screw to mount to the back of the top handle. This extension allows for a longer grip length as well as ergonomic finger shaped grooves for added comfort while handling the camera.