I saw yesterday that Mophie released their Juice Pack Air for the iPod Touch 4. While I do not have the 4th Gen device, I did pick the Juice Pack Air up during the holidays for my Gen 2 iPod Touch. I originally had their first version which was like a sled. It did not offer full case protection like the Juice Pack Air. I really like this air design as it is essentially a case as well. It also has an on off switch for the extra power.