CKR makes closed cell foam products including the following:
Water or Gas Valve Box Mud and Debris Plug - Writeable Surface, Higher Density
Water or Gas Valve Box Mud and Debris Plug
Meter Pit Insulation Disk Pit Plugs - Protect Water Meters in Round Pits from Freezing
End of Pipe Night Plug, End Plug construction Animal Guard, Tapered
CKR Manhole Rehab Plug