Spun Aluminum Gravity Ventilator, Size 18, Model GRS-18
For natural gravity or positive pressure systems, model GRS offers excellent performance and durability for intake or relief applications. Featuring an exceptional low silhouette design and rugged construction this model is both efficient and economical. Features: All aluminum exterior for corrosion-resistant construction, Integral birdscreen to prevent entry of birds and small objects, Built-in curb cap with prepunched mounting holes for easy attachment to roof curbs