Description: This set of magnetic detecting switch monitors the opening and closure of doors and windows used to protect doors and windows for the most part. It is great for installed on doors of house, garage, warehouse, enterprise and shop etc. Specifications: Condition: 100% Brand New Material: ABS Plastic Color: As Picture Shown Operating Voltage: 1.5V Transmitting Frequency: 433MHz Battery: 1 * AAA Battery(Not included) Battery Life: About 2~3 Year If it is opening and closing 5 times per day Transmitting Distance for Many Main Unit: 100~200m/328.1~656.2ft(open area distance) Size: Approx. 7.3*2.5*1.5cm/2.87*0.98*0.59in, 3.8*1.1*1.1cm/1.5*0.43*0.43in Weight: Approx. 30g Package Included: 1 * Set of Wireless Door Magnetic Detecting Contact with Adhesive Note: 1.Can not used alone. Should work with the alarm system main unit for alarming. 2.The indicator light will flash once in every 3 seconds while it is in low battery status