LensCoatA(R) for the Canon 100-400IS f4.5/5.6 LensCoatA(R) telephoto lens covers 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. Please note that the The LensCoatA(R) Canon 100-400 IS cannot cover the fixed portion of the lens barrel due to the manner in which the lens barrel extends/retracts leaving approximately 3 inches exposed when the lens is fully extended. If you have the new IS II version then you want this cover Canon 100-400 IS II.