• Congratulations to Centerline Development on their new Coneqtec HS-57!

The patented, accurate manhole riser/collar system

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Whether replacing an old manhole riser installation or working on a new project, the Whirlygig system is for you!

Whirlygig is a revolutionary method of manhole riser/collar installation. A patented process, it is size accurate, installed in minutes and leaves no doubt about quality control. Cast-in-place on site, our manhole riser/collar system is ideal for new construction or rehab projects.

Over 90 thousand installations across America.

The Whirlygig system is:

  • Easy to install. Please watch our video on this page where each step of the process is explained in full detail. You will be amazed!
  • Streamlined installation is a snap and works everytime.
  • Sturdy - Our high quality pre-formed thermoplastic form is constructed to outlast any other system available.
  • Please see our Specifications Page for compete details.

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