1pair 20m Simple Beam Alarm Photoelectric Infrared Sensor Detector Home Door Security System Description: This pair of infrared detector need install them at the opposite positions. There is a infrared area between these two detector parts. When someone passes the infrared region for an adjusted response time, the detector will send alarm signal, great for security system in school, office building, hospital, parking and home yard, etc. Features: Made of plastic shell, eco-friendly, durable and sturdy e. Create a reliable and invisible infrared beam up to 20 meters. Infra-red frequency: 1.92Khz; Power supply: DC 12V; Wave length: 940nm. Half egg shaped, input: RX 15mA-TX 30mA, operating temperature: -10℃ to 70℃ Range can be reduced to 30% in bad weather conditions: fog, rain, dust, etc. Specification: Condition: 100% Color: Black Shell Material: Plastic Receiver Range : Less than 20m Infra-red Frequency: 1.92KHZ Wavelength: 940nm Voltage: DC 12V Input: RX 15mA-TX 30mA Operating Temperature: -10℃ to 70℃ Relay Output: 1A maximum 30V, constant open/close, can be set by jumper wire Size (L x W x T): Approx. 76 X 49.2 X 21.6mm / 3 x 1.9 x 0.9inch Package Weight: Approx. 130g Package Included: 1 x Transmitter 1 x Receiver 1 x Set of Accessories 1 x User Manual Note: 1. The best installation height should be more than 20 cm, distance is not less than 2 meters.  2. Infrared protection device should be installed vertically, and at the same level. 3. First installing receiver, then installing transmitter. When the off light of receiver is turning off, then fixed it, installation finished. 4. Distance between receiver and transmitter need be more than 1m, otherwise it will be insensitive phenomenon. 5. Please note that the new type and old type of this product will be sent randomly and make sure you will not mind before ordering.