Currently available in sizes 42” through 64” 

SIGMA is the leading supplier of Pipe Restraint Products to the North American waterworks industry. As a company that is dedicated to industry innovation, SIGMA is well known for its One-Lok wedge-action restraining glands and bell harness restraint products. Steve McDonald, SIGMA’s Pipe Restraint Product Manager, explains the significance of the “re-rounding” concept of our wedge-action restraining glands for ductile iron pipes.

“The re-rounding feature is a patented and revolutionary feature because it provides a solution for the occasional event when larger diameter ductile iron pipes onsite experience out-of-round or ovality issues. The re-rounding capability allows for immediate reconciliation of the ductile iron pipe’s diameter and ensures proper restrained joint assembly at time of installation. When required to utilize this re-rounding feature, the installer or contractor can bring the pipe back to its normal outside diameter, thus enabling the pipe spigot end to fit appropriately into the mechanical joint outlet or ductile iron pipe bell. No external equipment is required such as hydraulic jacks that can cause damage to the standard cement mortar linings or more expensive interior coatings. SIGMA CORPORATION…..committed to product development and industry innovation.

Please direct all inquiries for availability to your local SIGMA Sales Office or Steve McDonald at