Quite the validation if you ask me!
Rent Canon EOS 5D Mark III Magic Lantern RAW
Here's the additional info from their page:
• Magic Lantern is an add-on that runs off an included SD card. You can still access all of the 5D Mark III’s native firmware functionality. If you need to access this native firmware instead of using Magic Lantern, press and hold SET at startup to bypass Magic Lantern for that session of use.
• Do not attempt to update the native firmware of the 5D Mark III.
• The camera has been updated to Canon firmware version 1.1.3, which Magic Lantern is designed to work with. Magic Lantern does not contain any Canon code and runs alongside the official Canon firmware as a separate task. Again, do not attempt to update the native firmware.
• SD Card with Magic Lantern Pre-Installed
• Lexar 128GB 1000X CF Card
• Magic Lantern RAW Install instruction manual
• Body cap
• Camera strap
(cover photo credit: snap from the site)