Can anyone tell me what an; "idle bar" is or does in a glow plug?

prevents fuel splashing on the element during idle

Thanks for the info; I had found some on eBay for sale, and didnt know what the idle bar was or did. After reading up on them, I was scared that the bar could contact my piston and decided to pass on purchasing them. Ialso read that the idle bar, can cause the engine to not reach full high RPM.