AGPtek Good For Campers Digital Satellite Signal Meter Finder Meter For Dish Network Directv FTA LCD Graphic Display Backlight Compass Buzzer Control High quality component. Anti-corrosion connectors Built-in amplifier compensates insertion loss Sensitive meter for in-line use; pocket size and light weight With electronic buzzer. Easy operation, attenuation, audio tone and back light Powered by the receiver, nice tool for campers. PS: work great with directv hd swim signal; it uses 2X1.5v lithium batteries