Component ID on board say's RV, looks like MOV?

I'm working on a 220V A/C powered plasma cutter. I'm trying to identify an input power line component on a small filter board. It's ID on the board says "RV" it looks like an A/C protection MOV to me. It's used in parallel with a 100K 2 watt resistor and a few 475V Caps across the two 110V opposing wave A/C lines. I think the board's function is to made a 0V point for DC startup power on the main board. I might be wrong though.

Can anyone shead any light on what a RV is? it's yellow in color 3/4" dia.

Thanks
Jay

Update, It is a MOV. I should have just trusted myself.
Sorry for the usless post.