This is an upgrade from the SMS110... Milwaukee MC110 pH Monitor, Set Point 3.5-7.5pH. The MC Monitors are designed to continuously monitor pH, EC or TDS values directly in your reservoir. Each unit features a user selectable set-point. An LED visual alarm is activated and flashes when the pH, EC or TDS level rises either Above or Below (user selected) that set-point. All these instruments run on a 12V adapter so there's no need to worry about failed batteries and each unit comes with mounting kit, probe, probe holder and starter calibration solution. Professional pH monitor especially designed for use with aquariums. •User selectable Hi/Low Set Point •Manual 2 points calibration •Visual LED alarm •Supplied with 12 VDC adapter, mounting kit, and 20ml pH 7.01 calibration solution •Double junction pH electrode with 2m cable (BNC connector