Smith-Blair's 431 RazorLock wid range, two bolt, restrained coupling redefines the market by delivering unmatched speed, ease, and reliability.  Featuring a single Dual Drive bolt on each end, the RazorLock accommodates a wide range of pipe in both size and materials, while integrating proven restraint technology for secure connections. 

RazorLock incorporates advanced, patent-pending features, including bolting innovations, molded gaskets with armor, controlled flex technology, and precision restraint components. Adapted from Smith-Blair's 30 years of expertise in natural gas restraint technology, RazorLock builds on the proven success of the EZ Maxi-Grip coupling, trusted in hundreds of thousands of installations across the U.S.

The RazorLock coupling is constructed from premium materials designed for durability and performance. The sleeve is made of cast ductile iron per ASTM A536, providing exceptional strength. The flange is cast from ductile iron per ASTM A536 or cast carbon steel. The gasket is Buna-N per ASTM D2000, molded (not extruded and spliced) with molded-in corrugated ¼ hard 304 stainless steel armor per ASTM A240. The one-piece, near-full circumferential wedge-shaped grip ring is carbon steel per ASTM A36 or ASTM A513 heat treated. Hardware consists of stainless steel per ASTM A193 & A194 with anti-galling coatings. The coupling features a fusion bonded epoxy coating per AWWA C213 for corrosion protection.

The RazorLock coupling has a working pressure rating of 250 PSI and a test pressure rating of 375 PSI, with restraint capability of 100°F ΔT HDPE DR 9. It is designed for use on multiple pipe types including PVC (DIPS-DR25, IPS-SDR26 min. thickness), PVCO (CIOD PC235 min. thickness), PE (DR32.5 min. thickness with stiffeners required), ductile iron, carbon steel, and cast iron (must be round and smooth). The coupling is available in 4" and 6" nominal sizes, with the 4" size accommodating pipe outer diameters from 4.44" to 5.06" and the 6" size accommodating 6.56" to 7.16".

*Please visit the Resources page on our website to view the High Density Polyethylene Pipe (HDPE) guide with more specific information on how to use our products on HDPE pipe.

Out of the box, RazorLock couplings are "stab fit", requiring no disassembly to install. A handle on the sleeve provides a means for ergonomic transport and maneuvering of the coupling into position for installation. To eliminate complexity, the design utilizes a single gasket, with no secondary gasket required. 

RazorLock is the first Smith-Blair product to feature the innovative patent-pending Dual Drive Bolt, designed for faster, easier installation. This unique fastener can be tightened with ASA B5.38 ½" square drive tools eliminating the need for sockets, or alternatively with standard-depth heavy hex sockets. As the installer tightens the bolt, the flanges bend uniformly compressing the gasket and the one-piece grip ring through flexure points strategically positioned on the flanges inside faces, preventing point loading and "egging" of the pipe. The grip ring's sharp, multi-length teeth engage around the pipe, protecting its integrity while distributing thrust loads. As pressure increases, hydraulic force enhances the grip ring's engagement, pushing it tighter around the pipe to ensure a secure connection.