Oil caps keep the engine's oil from spraying out of the filler hole during operation. While they may vary in size, color, novelty functions and the like, they are essentially nothing more than caps.
If you've lost or broken your oil cap, replace it so your engine doesn't leak oil everywhere!
Probably one of the easiest parts on a car to replace, simply unscrew one and screw another back on.
We stock oil caps from these manufacturers: