I needed something to hold and pad my PL45mm and Zuiko 9-18mm inside my camera backpack, so that they'd be protected and not try to fall out. I'm not sure what made me think of it, but on checking online and doing some measuring, I found that these things are just the right diameter (only for the barrel of the 9-18): View attachment 277891 And, if doesn't work out, I can always use them to hold beer cans. Next step is to make some sort of removable attachment for holding them in the backpack.