I just took my TST's on their maiden voyage of 2000 miles. No problems and couldn't be happier with their performance.
They need to work on installation a bit. On my coach, the wrench is against the wheel on my inside dual valve stems and I had to remove the sensor and put the wrench on 180 degrees from the original placement in order to remove the wrench from the sensor after installation. To adequately tighten the sensors on those same valve stems, I modified the tool by cutting a portion of the "wings" off to give me enough clearance to rotate the tool easily. Others have commented on the wrench. Just do a search on TST tire monitors.
Pete - Full Timing
2000 Country Coach Magna 40', CAT C10, #5892
2006 Jeep Liberty