This is a spare glass LCD protector for use with the GGS Viewfinder Loupe. The GGS Viewfinder Loupe allows the photographer to quickly switch the loupe between two cameras. The GGS viewfinder loupe attaches to the camera using a separate (supplied) screen protector. This product is an additional screen protector. The protector is installed over the camera LCD where it protects the screen from scratches and impacts. The Viewfinder Loupe simply clips onto this screen protector and unclips again when not required. Features: The protector is designed to fit cameras with standard 3 inch, 3:2 aspect ratios screens such as the Canon 5D Mk2, Nikon D3s etc. It will not fit wide format screens such as the Panasonic GH series cameras. Outer Size(The screen and Border): 71mmx57mm approx. Inner Size(The clear screen): 60mmx45.5 approx. ...Contact us if you need more help.