The Hydra Series is extremely rugged and able to operate in diverse environments. Its operating range is 0 to 60C, and it is tested to stringent shock and vibration standards. Hydra's sturdy metal chassis effectively shields against electromagnetic interference, maintaining high measurement accuracy on low level signals. The analog circuitry is also isolated from the digital circuitry so you can measure high voltages directly (up to 300V ac rms). And it conforms to I.E.C., C.E. and CSA safety standards. What's more, all set-up information is battery-backed, so it's immune to power failure. Hydra will return from a power loss and resume scanning, while all configuration information and stored data remain intact. Option 901 adds Hydra Software for Windows.