Well the one I was referring to earlier was made by a company called Gruber, but looking around it may no longer be made. I did find this one however...
http://www.amazon.com/PowerStar-PS-6.../dp/B001FXY7NW
And another quick search showed that like I said above, the difference between a 680 and a 680MJ is the MJ version has a "M"etal "J"acket around the battery. Not really needed, but also doesn't hurt either I suppose.