ALTA RCXL is the largest-size model (#4 in our range of 4) and is perfectly fitted to protect a DSLR with a 600mm F4/400mm F2.8 or other large pro telephoto lens attached.
The Alta Rain Cover is a simple yet ingenious shooting in the rain solution designed to protect a wide array of different camera and lens set-ups without creating undue hassle or hindrance.  When caught in a sudden downpour, pull the cape out of its pouch to protect your camera and lens. The intuitive design ensures no wasted time fumbling to get the cape onto your gear. This flat spread out cover lands right on your camera and drapes around in split seconds. All you need to do next it secures the hook-and-loop fastener around the lens, and the hook/loops underneath to prevent it from blowing up in a gust of wind. 
To fit the hook/loops, simply slip the hook on the elasticated cord under the tripod canopy (to ensure it doesn’t lift), then slip it through the first loop and then hook onto the second loop. Alternatively, keep looping through until it is as tight as you need it to be.  
Being an open ‘cover’ and not a closed sleeve cover, we ensure ease of use for all sized hands as well as the possibility to use with gloves on, but most importantly this design prevents condensation so that we can promise you 100% clear viewing of screen, controls, and viewfinder through the transparent TPU window on the back. The Alta Rain Covers have an incorporated accessory pocket under the rear viewing window and all come with an included pouch so that they can be folded up neatly and fit compactly in any bag or pocket.
Carry an Alta Rain Cover with you year-round and never get caught off guard.