The AT4 4-Channel Annual Event Timer from Altronix is a 24-hour, 365-day event timer suitable for home and building automation, security, access control, and lighting control applications. This unit is equipped with four form C relays that operate independently. The AT4 enables you to program up to 254 individual daily or weekly events. Block programming capacity accommodates a total of 1778 events per week. In addition, you'll be able to program up to 254 holiday dates. AC failure supervision is provided (backup battery available separately).