SOLD OUT, check "used mercury switch" and the "mercury replacement" category.  The Mercury Flame Safety Switch is found in many older gas fireplaces made by Majestic/Insta-flame, Empress, Heatn'Glo, Hunter, Napoleon, Hevac, Clare and others. Due to the hazards of Mercury, this part is no longer produced. and once current stock has been sold 1000's of fireplaces will not be useable if this part fails.