O-Jet Minispray. The flowrate of the microsprayer is determined by the color of the O-Jet. At 20 psi black heads are 6 gallons per hour, blue heads are 10.4 gallons per hour, and red heads are 24 gallons per hour. They are avaialble in a strip spray, 90 degree, 180 degree, and 300 degree patterns.