Additional Features: True dual-channel power meter - two simultaneous power readings Fast measurement speed (up to 100 readings per second, over the GPIB, with E-series sensors) Speed improvement of x2 using the 8480 series power sensor (compared to the 437B) No range-switching delays with 8480 series sensors, and only one fast-range switching point with E-series sensors Code compatibility with 438A power meter GPIB and RS232 connector for remote control of all functions Internal rechargeable battery option provides up to 4 hours continuous use (option 001) The Agilent E4419B Power Meter is an economical, high-performance, dual-channel, programmable power meter.