if purchased directly from the manufacturer, Jolly Logic.Amazingly tiny and incredibly powerful, the AltimeterTwo uses state-of-the-art pressure and acceleration sensors to perform 10 key flight analyses for each rocket flight, including altitude, speed, acceleration, and flight duration.No batteries required: the AltimeterTwo plugs into just about any USB port to recharge.Its durable construction and convenient tether point make this the only rocket altimeter that can be mounted in just about any rocket--even those without a special payload section.Although data is NOT downloadable, every key statistic is compiled and presented clearly on the sunlight-readable LCD screen.