The SBL-33S-406-1WSBL 3000 series is a 6 Digits 4" Digital Wireless School Clock that allows you to choose specific features in order to meet your facility’s needs. The SBL 3000 can accomplish more than simply displaying the time. Some additional features include Elapsed Timer capabilities, programming the clocks through Sapling’s software program and the ability to interface with other systems. Working on Sapling’s 915-928 MHz frequency-hopping technology, the digital wireless clocks have the ability to receive and retransmit the time to neighboring clocks. No need to worry about interference occurring, Sapling’s patented technology allows each clock to frequency hop the transmission of the signal, enabling the clocks to receive and display the correct time, even if there is interference on a particular frequency.