I love the design and performance of these sensors but all 4 showed signs of having been previously installed. Two had severe dents and abrasions on the aluminum housing and all 4 had the screws attaching the sensor to the stem housing already installed in the housings to the point where the thread lock activated. So now the screws are engaged. Heat may have weakened them but I didn't have to apply heat to install what was supposed to be a new item and obviously I have doubts about the battery life and functionality if someone has already installed and returned it.