Defender motion detector battery operated PIR alm will detect up to 7mt 90 degree angle detection, 4 digit arm and disarm. can be set on silent arm with auto dial up to 3 phone numbers. Auto reset. Just connect to telephone line for auto dialler. facility to record 6 second message, 30 second Exit 20 second entry low battery indicator, uses 4 AAA batteries. Ideal for home security, workshops, offices, etc.