Twsbi - a Korean pen manufacturer - had some bad plastic in one of their production runs, the body of the pen would crack in its threads at the tail of the pen

They handled it properly, I sent them an email with a photo of the damage, they asked for my postal address and sent me a replacement body. The reassembled pen has been working happily now several years later

I now have five twsbi pens (four piston fillers, one vacuum filler - the vac mini doesn't leak on planes)

I have never tested the warranties on Zippo lighters or Maglite lights

*Edited spelling of twsbi