Poor design
"I have used this roller possibly 3 times, I store it in the canister it came in just for extra protection. For the last month, all I could smell was this oil in my purse, not like it was a bad smell, but unusual that I could smell it so strongly. Checked the lid, checked the bottom, everything checked out. Today I got to use it for the first time in weeks to find the vile is completely empty, it appears to have been leaking from where the roller ball is. A pretty expensive thing to have used less than 5 times, and of course it's past the return/exchange policy"