welcome to our shop! describe: This set of magnetic detection switches monitors the opening and closing of doors and windows, and is mostly used to protect doors and windows. Ideal for installation on doors of houses, garages, warehouses, businesses, shops and more. feature: This is a set of magnetic detection switches mainly used to protect doors and windows. Guards monitor the opening and closing of doors and windows. 433MHz transmitting frequency, wireless connection. High-quality magnetic sensor contacts, strong magnetism, responsive and durable. Built-in different code switch, suitable for most GSM or smart home security devices. Easy to install and use with adhesive. A good replacement for old contacts. Ideal for installation on doors of houses, garages, warehouses, businesses, shops and more. Specification: Condition: 100% new Material: ABS plastic Color: as shown in the picture Working voltage: 1.5V Transmission frequency: 433MHz Battery: 1 AAA battery (battery not included) Battery life: switch on and off 5 times a day, about 2 to 3 years Multi-host transmission distance: 100~200m/328.1~656.2ft (distance in open area) Dimensions: approx. 7.3*2.5*1.5 cm/2.87*0.98*0.59 inches, 3.8*1.1*1.1 cm/1.5*0.43*0.43 inches Weight: approx. 30g Package includes: 1 set of wireless door sensor detection contact adhesive notes: 1. Cannot be used alone. It should cooperate with the alarm system host to issue an alarm. 2. The indicator light flashes every 3 seconds when the battery is low. Please allow slight errors due to manual measurement and different monitors. (Customer satisfaction is our top priority. If you find any product problems after receiving the goods, such as damage or incorrect quantity, please contact us immediately. We will try our best to provide you with satisfactory after-sales service. Thank you for meeting me. I hope this helps you. wish you a happy life.