1byone Wireless Driveway Alert, Infrared Motion Sensor with 1 Plug-in Receiver and 2 Sensors Reliable Range - Communication range of up to 100m/328ft (the distance from the sensors to the receiver In THE OPEN AIR) and detection range of the infrared sensor of approximately 5-8m/16-26ft to effectively keep you alerted. Different Ringtones - The receiver is a doorbell design with 36 different ringtones for personal preferences. User-Friendly - There are 3 mode choices (Sound/LED Flash/Sound and LED Flash) and 3 levels volume adjustment (High/ Middle/Low ) from 25-80dB. PIR Technology - Our sensor uses state-of-the-art passive-infrared (PIR) sensor to detect any movement within the detection range. Perfect for long or hidden driveways and allows you a fore warning when guests (or intruders) are approaching. Expandable & DIY: 1 receiver can pair up to 5 PIR sensors and 1 PIR sensor can pair with multiple receivers. If you have more than one driveway or area you would like to monitor, just DIY and fulfill your needs.