Certainly some e-cigs use flat-topped batteries, and some torches don't care which kind, and some torches insist on button topped, and some torches and e-cigs don't accept the full range of lengths which these batteries cover, only a few mm difference, but sometimes that last mm matters.Thanks for the replies, thought I was subscribed to the thread but wasn't so got no notifications. With regards to the e-cigs, I heave seen somehwere that they use a flat topped battery, unless that info was wrong?