This product is small in size and easy to carry. It will not be a burden for the elderly or children. It will dial your telephone number or mobile number if there is voice higher than 45bD in 4 meters. Specifications: Card compatible: GSM / SIM Microphone Range (meter): 5-7 Radius Receive sensitivity: about 10K GPRS Working temp: -40 to 50℃ Responding frequency: 1.2K-800Khz Stand-by time: 3-5 days (without voice control), 10-15 days (without voice control) Work frequency: 850MHz, 900MHz, 1800MHz, 1900MHz (please check if it can work with your local system format before purchasing) Battery: 1 * 3.7V, 300mAh Li-ion battery Item size: 35 * 20 * 14mm / 1.4 * 0.8 * 0.6in Item weight: 25g / 0.9ounce Package size: 60 * 60 * 30mm / 2.4 * 2.4 * 1.2in Package weight: 25g Package list: 1 * Voice System 1 * USB Cable 1 * User Manual