This is an optional HTS-SS Sensor Station from Hitec. FEATURES: New Telemetric AFHSS System Compatible with Aurora 9 and Spectra 2.4 module Sensor Station (HTS-SS) - collects all data from each sensor, sending it back to your transmitter via the Optima 7 or Optima 9 omnidirectional receivers GPS Sensor (HTS-GPS) - displays constant directional information such as: speed, altitude, latitude and longitude Temperature Sensor (HTS-TEMP) - measures temperatures from -40 to 392 degrees Fahrenheit Optical RPM Sensor (HTS-ORPM) - provides optical RPM information Fuel Level Sensor (HTS-FUEL) - provides an accurate 5-step reading of your remaining fuel level when simply attached to the outside of the fuel tank Magnetic RPM Sensor (HTS-MRPM) - provides RPM information using a magnetic sensor INCLUDES: One HTS-SS Sensor Station One adapter Instructions REQUIRES: Airplane and appropriate system SPECS: Length: 37.8mm (1.49") Width: 27.5mm (1.08") Height: 8mm (0.31") lmm 9.30.10 ir/jxs