The Model 464 Electronic Pump Control Unit is available in 125 psi or 250 psi versions. It uses 4 x AA alkaline batteries that last up to 100 hours of normal use. These controllers can also be operated manually if your batteries run out in the field, using only a compressed gas source. It has automatic pre-set sample modes from low through high flow settings. Up to 99 user-created flow rates can be saved in FRAM memory. The controller allows faster purge rates and precise low flow control to ensure a representative sample at 100 ml/min or less when sampling for VOCs.