The most common chaser communications device is the cellular phone. These are used for both voice and data connections. External antennas and amplifiers may be used to boost signal transception. It is not uncommon that chasers travel in small groups of cars, and they may use CB radio (declining in use) or inexpensive GMRS / FRS hand-held transceivers for inter-vehicle communication. More commonly, many chasers are also ham radio operators and use the 2 meters VHF and, less often, 70 cm UHF bands to communicate between vehicles or with Skywarn / Canwarn spotter networks. Scanners are often used to monitor spotter, sometimes public safety communications, and can double as weather radios. Since the mid-2000s social networking services may also be used, with Twitter most used for ongoing events, Facebook for sharing images and discussing chase reports, and Instagram trailing in adoption. Social networking services largely (but not completely) replace forums and email lists, which complemented and eventually supplanted "Stormtrack" magazine, for conversing about storms.