Two Packaged Metering Manholes integrating 15-inch Palmer-Bowlus Flumes.  The manhole on the left will see vehicle traffic and has been provided with a H-20 reducer top to allow for the installation of grade rings, frame, and cover.  The manhole on the right is a domed top style and is intended for grassy / non-traffic areas.  

Both manholes are sized for the same surface grade - the traffic manhole is intended to be installed so that the reducer shoulder is 1-foot BELOW grade, while the domed top manhole is sized so that the top of the manhole is 1-foot ABOVE grade.