I have a set of 4 TPMS Sensors from an 08 express 2500 van that were only on the vehicle for the drive from the dealership to a shop to have custom wheels installed. they have no corrosion, cracks or damage of any sort and they have been in a box since removed. the number on them is s120123009a, siemens, and they fit a bunch of different gm's from 07-10. i'm pretty sure they fit impala, g6, acadia, and a bunch of others, but i'm not gonna guarantee fitment on anything. that's up to you to check. i would recommend replacing the seal on them, as you should every time a tpms sensor is removed, and they're only a few dollars from most parts stores or the dealer. looking for 75 or best offer for the set of 4. email me at hallass@gmail.com