Specifications: Alert with red light& sound when pedestrians are approaching. The infrared wireless system alerts you the moment someone enters your property. What's more, the receiver can pair with up to 50 sensors, giving the ability to secure a large area. With this system, you'll always have advanced notice that someone's on their way to your door. The compact, discreet motion-sensor unit installs on garage, mailbox, fence post... nearly anywhere. Item Name: Alarm System PIR Sensing Angle: 40°  PIR Sensing Distance: 5-8M  Working Range: 125M  Emission Frequency: 433MHz  Ring Volume: 1-100dB(within 0.5m)  Alarm Mode: Sound + LED Light Flicker  Two Alert Choices: High Volume/Low Volume  Quantity:  Type 1: 1Pc Sensor Type 2: 1Pc Alarm + 1Pcs Sensor Type 3: 1Pc Alarm + 2Pcs Sensor Type 4: 1Pc Alarm + 3Pcs Sensor Type 5: 1Pc Alarm + 4Pcs Sensor Type 6: 2Pcs Alarm + 2Pcs Sensor Power Supply(Receiver): 3 x DC 1.5V C Batteries (Not Included)  Power Supply(PIR Transmitter): 1 x DC 9V Battery (Not Included) Alarm Size: 9cm x 12.8cm x 3.5cm/3.54" x 5.04" x 1.37" (Approx.) Sensor Size: 6.3cm x 11cm x 4.5cm/2.48" x 4.33" x 1.77" (Approx.) Notes:  Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: Type 1: 1Pc Sensor + Accessories + User Manual Or Type 2: 1Pc Alarm + 1Pc Sensor + Accessories + User Manual Or Type 3: 1Pc Alarm + 2Pc Sensor + Accessories + User Manual Or Type 4: 1Pc Alarm + 3Pc Sensor + Accessories + User Manual Or Type 5: 1Pc Alarm + 4Pc Sensor + Accessories + User Manual Or Type 6: 2Pcs Alarm + 2Pcs Sensor + Accessories + User Manual Alert with red light& sound when pedestrians are approaching. The infrared wireless system alerts you the moment someone enters your property. Whats more, the receiver can pair with up to 50 sensors, giving the ability to secure a large area. With this system, youll always have advanced notice that someones on their way to your door. The compact, discreet motion-sensor unit installs on garage, mailbox, fence post... nearly anywhere.