Wireless infra-red PIR sensor will trigger alarm if there's any activity.
eBay
Wireless Welcome Doorbell Features ● Shop Keeper in day time, anti-thief in the night, welcome /doorbell /alarm / color lights/ lighting 5in1 multi-function ● Remote transmission range up to 280M/918ft in the open space ● 8 chord music chip, 40mm big horn,36 chime melodies, remember your last set melody and volume level once powered off ● Colorful LED lights, adjustable brightness, distinguish multiple entrances by different colors ● 4 stages adjustable volume (Loud/High/Middle/Low ) from 113-25dB ● Receiver can learn from up to 32 wireless sensors like PIR motion, magnetic or vibration sensor as well as up to 8 remote controllers. Application: shops, Commercial Complex, Luxury hotels, offices, factories, homes, villas, driveways, walking paths , Supermarkets ,restaurants etc.
eBay
Play the music you select in music /doorbell mode. It is used directly after receiving, put in battery and adjust angle to avoid false alarm, not suitable for outdoor because of lack of waterproof function.
eBay
Keyhole for wall mounting or can be free standing. Sensing distance up to 5m (depending on light conditions).
eBay
A light sensitive, motion activated door entry chime suitable for office and retail locations. With a range of up to 8 metres and 120° detection angle this unit comes supplied with an adjustable wall bracket enabling you to achieve the perfect coverage fo.
eBay
Old retro entry plus visitor alarm been in the garage for years might need a clean new and still sealed free postage
eBay
Item Type: Entrance Doorbell. 1 x Entrance Doorbell. Detection Angle: Arc 120° (Ceiling Type). Induction Distance: ≤3cm. Support built‑in FLASH playback, more convenient. There are two modes of A, B.
eBay
It is used directly after receiving, put in battery and adjust angle to avoid false alarm, not suitable for outdoor because of lack of waterproof function. ♫ Brief Introduction Led indicator light.
eBay