JD-2 can be used for Differential, Pressure, and Vacuum applications.

Blue: .07" to 1.7" W.C. 801111301 (2mm to 43 mm W.C.)
Grey: 0.1" to 4" W.C. 801111302 (3mm to 102mm W.C.)
Purple: 0.1" to 10" W.C. 801111310 (3mm to 250mm W.C.)
Red: 0.1" to 24" W.C. 801111303 (3mm to 600mm W.C)
Orange: 5" to 35" W.C. 801111315 (125 mm to 875mm W.C.)