My attempt at a Whatsit..

[davesnothere11]

Too small for a stove burner so maybe a butane lighter of some sort.

 

[shuttervelocity]

Light bulb?

 

[Aloicious]

great guesses, but still nope...I should mention the image in the first post is like 10%ish upsize on a 100% crop of a full 1:1 macro....the wider shot is a little less than 100% crop of the same 1:1 image.

another hint, they help make you go...

and an expansion on the previous hint....although many people rely on the use of these very frequently, some people may not even look at them, or even think about them, until they stop working...

 

[shuttervelocity]

I though spark plug which would fit your description and there are FG spark plugs as well.

 

[Aloicious]

pretty close, but not quite there....it's definitely automotive related.

 

[MTVision]

Head gasket - or whatever they are called

 

[480sparky]

Thermostat

 

[Aloicious]

I'll give you one more wide view before I head off to work, it should make it a bit easier...if no one get is by tomorrow, I'll post up the answer...

 

[davesnothere11]

Fuel injector?

 

[Aloicious]

Fuel injector?

ding ding ding! we have a winner...it's the business end of the fuel injector

 

[shuttervelocity]

Wow! Good one. But its been millions of years ago since I stared at the face of a fuel injector and probably would never have guessed it. LOL.