I’m not sure if the Molicel M50A would fit into flashlights. Its diameter is 21.7mm, i.e. larger than or at least as large as the inner diameter of many battery tubes of 21700 lights. I would be happy to test it, though (if I had a sample here). 
I’m not sure if the Molicel M50A would fit into flashlights. Its diameter is 21.7mm, i.e. larger than or at least as large as the inner diameter of many battery tubes of 21700 lights. I would be happy to test it, though (if I had a sample here).