The LR-500 Allows programming so users can only tune to certain channelsProvides exterior access to SEEK and channel selection capabilitiesIdeal for users who need to quickly conveniently change channels or easily SEEK to find a channel with a transmissionOffers maximum flexibilityIs ideal for personal use,schools,language translation,museums,and high interference applicationsField Tunability In the sometimes crowded world of RF,the ability to quickly change channels and avoid interference is a necessity:Listen offers 57 channels which are tunable on-site using UP and DOWN buttons.It s as simple as that! Look &Listen Display No need to guess battery level status with our 3-stage indicator! Digital Listen receivers are digitally-tuned so transmission won t drift;assurancethat when you select a channel,it stays on channel!SmartChargeBatteries wont overcharge! Charging circuitry is conveniently built into Listens receivers; never worry about unplugging a transformer at a certain time. Save money and eliminate hassleAdvanced Nickel Metal Hydride (NiMH) rechargeable batteries,which can be recharged within Listen s products, have no memory effect and can last up to ten times longer than typical NiCAD batteries. SeekPress SEEK to find an in-range transmitting channel; perfect for personal use.