668D-13-1 is a low cost series 668B compact differential pressure transmitter with bottom connection. This is capable of sensing differential gauge pressure with ±0.8% FS accuracy and converts this pressure difference to a proportional high level analog output for both unidirectional and bi-directional pressure ranges. The compact, lightweight design makes installation simple and easy. Units are protected against incorrect wiring, and include a protective terminal cover. Typical applications include HVAC and VAV control, clean rooms and isolation rooms and duct static pressure measurement.