Why yes, yes they are. But, you have to have one that fits your sensor. Most places that do tire work will have a repair kit with some assorted stems and parts. The guy down the street from me had to replace one of my stems when his apprentice broke it removing one of my tires.
2010 KK Sport, Detoures Knucklebone & backbone, smittybilt XRC 10, rigid led lights, R/L sliders & rack, cb, EMT2, R/K 15x7, OME, JBA, mopar skids & hitch, headlight covers, 4.10's and TruTracs