Rex has both types. I also have some, (I bought 10 because they're "biswitchable"), either/or switches. 4 blades, 2 for an ignition, or two for a mag. I can give you the website when I get back to Bullhead, or send you one for about $15. + the shipping...Ray
PS why do you call it a "Mercury" switch? You are referring to a kill tether switch, right??