Found these for 5 bucks in an antique store next to some junk... They're really active on my meter.. Lots of thorium The paper envelope they came in is crumbling but the mantles are intact... No idea how old these might be Sears 7411 Duplex Weave Rayon Mantles
@Les Vaughn IM mixed between using them or saving them. My guess is 1950's because I have never seen "the worlds largest store" logo. Dunno...maybe I should put them in a frame.