LensCoatA(R) for the Canon 300 f/4 with IS LensCoatA(R) 300-4 telephoto lens cover offers your valuable equipment some protection from scrapes and bumps, preserving its resale value. It also help break up the shape of your lens, making it less noticeable to wildlife. The LensCoatA(R) 300-4 features a clear plastic windows over the auto focus and Image Stabilization controls, and also the distance scale. The hood piece is designed to slide over the barrel.