This is a relic from the 1960s I think. Use for spreading medication like menthol in the air, or just adding humidity. Extremely simple no moving parts, it works by immersing electrodes in water which causes it to boil. Don't worry, the live parts are well-enclosed.
Folks are asking rather more for this on other selling sites, so here's a bargain.
I'm Bill on Shadeland just below Marshall.