Radio mini-barriers for the protection of doors and windows, height 1 m, with robust profile. Option of indoor or outdoor installation. Optical/acoustic synchronisation, protection from sunlight, powered with 4 x 3.6V - 2.7 mAh batteries (included) with life of 2.5 years, audible low battery warning. Range up to 5 m. Advanced security RF protocol, transmission frequency 868 MHz, transmission of ''contact open/closed'', ''tamper open/closed'’, unobstructed RF range of up to 300 m, unique ID code.