Hi clee and welcome to MobileRead. I've had a 505 for over a year now and really like it.
I use an MEdge Executive cover for regular reading and an MEdge Leisure cover for the gym, travel and beach. The Leisure cover has a padded inset you place the 505 into then the cover, which is clear plastic zips shut. Although not waterproof it is water resistant thus good for the beach, a boat and at the gym.
And, when I travel, I place the 505 into the Leisure cover screen first to give it a bit more protection in my carry on. You can read a thread on it here
https://www.mobileread.com/forums/sho...ighlight=Medge and get details on other covers in the Sony eReader Accessories section here
https://www.mobileread.com/forums/forumdisplay.php?f=113