Product Spotlight: Insulated Foam Plugs

SIGMA offers a wide range of insulated foam plugs, and currently has a stable inventory of DMPlugs, Valve Box Plugs, and Meter Pit Insulation Plugs.


The DMplug is a patented, inexpensive, non-pressure alternative for keeping debris and sediment from entering pipes and fittings. The tapered body allows for use in a variety of inside diameters without the expense of purchasing multiple plugs. The taper keeps it tight and in place. The DMplug will not absorb sediment or water, so the plug remains lightweight and ready for use time after time. Its use is not limited to pipe, but can be used in fittings or any round application.

DMplug benefits include:

  • Quick and easy to install, no pumps or tools needed
  • Inexpensive, one-size plug does the work of many
  • Efficient, the same plug can be used in bell or spigot ends of most pipes and fittings
  • A single plug will fit a variety of inside diameters
  • Wide range of sizes with overlapping plug OD ensures that a DMplug will fit
  • Made of lightweight, durable, non-absorbent closed-cell material
  • Plugs can be ordered to a specific size for a custom fit.

The DMplug fits in the Bell and/or Spigot end of PSM, IPS, C900, Ductile Iron, and any other pipe and fittings used in the waterworks industry.


The Valve Box Plug fits a standard valve box and is effective in keeping dirt, rocks and debris from collecting in the bottom of the valve box. Product features include:

  • High-visibility handle allows for easy removal
  • Made from closed cell foam that will not absorb water
  • Cut with a slight taper for easier installation
  • Maintains a snug fit that will keep the plug at the desired height in the valve box
  • Can be ordered to fit any other valve stem riser options


The Meter/Pit Insulation Plug is designed to protect meter pits from debris, rocks, and dirt from collecting in the meter pit.  Product features include:

  • Made of strong, durable 1.2# laminated closed cell foam with a 2.5 R-value per inch
  • Available in 4” and 6” thickness
  • Cut with a slight taper allowing a snug, easy installation
  • Taper keeps the plug tight and in place, sealing up any variations in the interior wall of the pipe. This ensures that the plug is doing the job to insulate.
  • The slight taper reduces plug tipping during installation
  • High visibility handle allows for easy removal

For more information about these and other Extended Products, please contact Craig Schapiro at