The Lexis is a hand-held 216-217 MHz FM transmitter with built in directional microphones. It's a very similar to (and compatible with) the HandiMic, which is part of the Microlink FM system.
Lexis is promoted by a group of hearing aid manufacturers as a competitor to the Microlink. Like the Microlink system, Lexis also has its own bootable FM receivers, but transmitters and receivers can be interchanged in some cases between these competing systems.
For more information about Lexis, see the primary