Hello, I used four Schrader EZ-sensors model #33500 (comes with rubber stem) along with the Model #34000 aluminum stem upgrade kits. I looked on this forum for guidance. As I remember, you recommended we use the EZ-sensors because they are dual-frequency. The sensors on my 2005 SRT6 are 433 MHz. The technician was able to program them using his TPMS tool (Bartec 400SD). But when the tool attempted to do the relearn process on my Crossfire, the relearn program terminated and said it was necessary to go to the dealer.