I've asked my pool company for them... I have to say, getting the City of Austin to inspect anything is a nightmare. It took 4 trips for the electrical inspector to pass us, the electrician and the city had a standoff because they city wanted more than their code required, and the electrician had a fight with them on it. The inspector and I had a nice chat, I found out what they were concerned about, installed a GFI that wasn't required myself, took photos, and the city was happy and passed the inspection. Now it's this... It might be remote sensor. To be honest, I talked to him about having the windows open and he said, we needed the sensors. He also told me he doesn't care if I remove them later, he just needs to see them so he can sign off on it. So, that's exactly what I'm going to do. The top of my sill is 53 and quarter, I'm going to temporarily raise that via a shim and double-stick tape. Then take them off. Seems like a waste of money, but it's small in the scheme of things and I just want this ordeal done with. The landscapers didn't finish last week, and when they left for the weekend, they had a nice slope from the crushed granite into the pool. We got nearly 6" of rain over the weekend and now what was my crystal clear pool is now a nice muddy red. Sheesh... Can't seem to catch a break on this one.