I have (2) wireless units I bought at Walmart. Not sure the brand, but I think it's "The Backyard Grill", $15 each.
I've only used them a couple times, so I can't speak for longevity, but they work great. I have the receivers sitting in the house while I"m doing other stuff and can see the temp at any given time.
Meat eater. Woodworker. PS3 Gamer. Home Theater Guy. Beer Drinker.
WSM 22.5 and random cooking stuff used to help form my shapely manly figure.