FG100 is the 1-inch wired flow sensor for ESP-ME3 (and ESP-2WIRE, which we do not stock). It is not a TM2 or RC2 accessory. Pair it with LNK2WIFI so high/low flow alerts show in the Rain Bird app. The sensor does not make a panel WaterSense — that is still controller + LNK2 + a rain sensor.