The new PMC AP3 Air Purge Spray and Pour Gun for Foam and Coatings. PMC designed and manufactured the AP3 Spray Gun, a second generation gun, with the contractor in mind. With multiple chamber sizes available, the AP-3 Gun allows you to create multiple spray patterns and pours on the job. Economical, lightweight, compact design. less parts than most competitive air purge guns. short trigger stroke reduces operator fatigue. Check valves for maximum cross over protection. Advanced design for pattern development and mixing.