Speedaire 4ZK91A Pneumatic Pressure Filter Regulator

Speedaire 4ZK91A Filter-Regulator packs filtration and pressure regulation into a single 1/2 in NPT FRL unit, delivering up to 120 CFM at 150 psi operating pressure and helping keep downstream tools clean and consistently pressurized. It uses a 40 micron particulate filter housed in a polycarbonate bowl with guard, with a durable aluminum body and a manual drain for straightforward maintenance. The 4ZK91A variant is listed as OEM Black NSMP, distinguishing it from other finishes, and features a top-mounted adjustment knob for precise pressure setting. Ideal for general shop air systems, it protects pneumatic tools, actuators, and spray equipment by removing particulates and stabilizing supply pressure, making it a common fit for bench tools and automotive or manufacturing setups that rely on clean, regulated compressed air. The unit’s 1/2" NPT inlet supports easy integration into standard air lines, and its 150 psi maximum operating pressure aligns with typical workshop compressors.