For the times that I need to use my 510 batteries, is there a small tank available? I ordered some C2s a long time ago from one of the suppliers and got a box of C2 shorts that worked perfectly. They were about the size of a 510 atty and unlike the atties they worked great. There are times when I don't want to use my mods or even my egos (when I take the wife to church or when I go to the hospital). Thanks for any info.