Hydraulic Cylinders Inc.’s Series 4 NFPA Tie-Rod Cylinders are heavy-duty pneumatic (air) cylinders built for industrial equipment, covering standard bore sizes from 1.5” through 8”. Made in the USA to NFPA-interchangeable standards with rugged steel construction, they deliver smooth push/pull motion while supporting consistent fit across common NFPA mounting patterns. Series 4 cylinders are available in any practical stroke length and can be configured with a wide range of standard mounting styles and piston rod sizes to match your application. Options include end-of-stroke cushioning to help reduce impact and improve control at full extension or retraction.