The basic package comes with a main unit, which is the temperature and calendar clock station, and a remote unit, the thermo sensor. The main unit has large read-outs for indoors temperature, calendar clock and temperatures collected and transmitted by the remote unit. The main unit can support up to three remote units. The main unit is capable of keeping track of the maximum and minimum temperature of different sites. And no wire installation is required and the RMR112 operates at 433MHz. As for the calendar clock, it is radio-controlled. It automatically synchronizes its current time and date when it is brought within an approximate 1500km radius of the radio signal generated from Frankfurt, Germany (DCF77). You can also set the calendar clock manually when it is off range. Other features include four-language display, four-step crescendo dual alarms and interchangeable display modes...