Bought this for my husband to replace the last vial he had. He had one similar to this and the inside vial cracked and started leaking oil. He liked the design, so I bought him this one.
Seems relatively sturdy and is easy to attach to a key chain and to remove when necessary.
Four stars because the inside vial cracked with the last one we had.
If you are careful with it once you have it out, though, it should be alright-- and my husband likes it.