Smart School Bell

Automated electronic school bell with battery operated function, it rings bell even without power (ac supply) for 2 days full day / half day modes max 50 periods possible per day exam modes 45mins, quarterly, half yearly, final exam modes plug and play option bell type. Also can be definable long bell, short bell, medium bell or combination of these three like long bell + short bell + short bell, long bell + medium bell, medium bell + short bell.