This item is a wonderful example of a useless object. It's a small oil canister, probably for one-time use. In order to open it you have to snip off the top, and once that's been done, it's probably impossible, or perhaps simply unadvisable, to keep the canister - more likely than not it would leak.

I'm sure that this canister came along with some electrical object which I once bought, but I don't know which, nor whether it's still in use. It probably isn't.