Prevost ALTO 4 Air Pressure Regulator — 3/4" & 1" FNPT, 7–145 PSI

The Prevost ALTO 4 air pressure regulator holds a steady downstream pressure on high-flow 3/4" and 1" lines. ALTO 4 is the large-body size in the Prevost ALTO air-preparation range, picking up where the smaller Prevost ATU regulators leave off at 1/2". A relieving diaphragm design vents excess downstream pressure when you dial the setting back, so the regulator responds immediately instead of locking in the higher pressure. The knob locks by pushing down, and a 1/4" gauge port lets you mount a gauge on either side. The modular ALTO 4 body stacks with the matching ALTO 4 filter and lubricator to build a 3/4" or 1" FRL train. Specifications Port sizes: 3/4" FNPT and 1" FNPT Flow rate: 177 CFM (3/4") / 212 CFM (1") at 87 psi, ΔP = 14 psi Adjustment range: 7 to 145 psi Regulator type: Relieving diaphragm, lockable knob Gauge port: 1/4" (gauge sold separately) Body: Aluminum alloy Series: Prevost ALTO 4 air treatment module Available Variants & SKUs SKU Port Size Flow Rate TR 204 3/4" FNPT 177 CFM at 87 psi (ΔP = 14 psi) TR 205 1" FNPT 212 CFM at 87 psi (ΔP = 14 psi) Flow ratings are taken from the Prevost 2026 US price list. Need a filter and regulator in one body? See the Prevost ALTO 4 filter-regulator.