As the most popular handheld gsm jammer, this product has a small size, easy to carry. Can block 8 frequencies, and have a very large jammer range. With a separate frequency control switch, you can select the frequency range that needs to be disturbed as needed. With car charger, can be used in the car. This product has the perfect heat dissipation system, can work long time. The shell is made of high quality metal with good heat dissipation.