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 Liberty KK Sport, deep water blue, weathertech in channel vent visors, weathertech digital floor mats, Detoures backbone winch mount w/smittybilt XRC 10 comp winch, rigid industries dually led lights on smittybilt fairhead mount, Rocklizard skink supersliders and Gecko safari rack, cobra cb w/48" firestick antenna, general grabber at2 245/75-16, OME heavy duty springs, OME shocks, about 3" - 3 1/2" of lift, Detoures Knucklebone spare tire and Jerry can mount, mopar skids, class 3 hitch w/7 pin wire harness, headlight covers, 4.10's and Detroit TruTracs F&R