Allegro Plastic Manhole Shield Part No. 9401-12 Constructed of rugged, lightweight Polyethylene with bright yellow material that resists fading. Will fit 27", 30" and 32" diameter manholes with an inflatable seal that ensures a watertight seal. Designed with 4-outrigger support gussets that stabilize the shield and is 12" tall to keep water and mud out of manhole as you work.