Based on the proven performance of the QR-25, an air compressor with over 80 years of reliable service, but engineered exclusively for natural gas applications, the Quincy QRNG™ is constructed of heavy-duty cast iron for strength and durability. The cylinders are cast with horizontal cooling fins and machined to rigid tolerances. The Quincy QRNG features an advanced-design pressure lubrication system, rebuildable connecting rods and low-lift valves. Optional gas unloaders available.