Our VP for Sensing Fluid Pressure called this sensor from Kavlico “sweet.” Needs a 5VDC 20mW power source, and will likely put out 0-4VDC, contingent on pressure, from 0-5"/H2O max, we’d say. Measures 1-5/16" x 17/32" on a pair of 7/8" long 5/32" slotted mounting wings. The upper 3/16" OD barb is the low side, and the lower is (ironically) high. Has a 3-pin connector with legend on the back for power and output. Call for a data sheet.

It's a nonpolarized bimetal heat sensor, 1/2" long with rubber sleeves and 6" long leads. It's also mysterious, because when used as a thermocouple multimeter input, it reads approx 94° in nearly boiling water but approx 170° in ambient air. Wethinks some sort of inversion or scaling is going on, but a person with your smarts will surely figure it out.

This 4" x 3-3/4" x 1-3/4" medical take-out air sensor has (3) ports coming off the main 3-1/8" x 3/4" ID chamber, (2) leading to one sensor and the other leading to a second one, then through circuitry on a mounted PC  board leading to a 10-pin output connector. Also has a PCB-mounted 3V coin cell battery. The sensors have input, output and trigger voltage and a voltage output, but we have no specs. Nice parts and pieces, though.