here's two vids I like where users have used the guts from ProVari mods to make their own box mods...someday I will do likewise, and I view my many tubes as just raw inventory to be used as needed, If the cells we are familiar with someday go away, I am fully prepared to yank apart my P-thingie tubes and somehow power them with whatever 4.2-4.5 volt power sources that will be available...