Self-Restrained fittings have blunt cast serrations which are specifically designed for PVC or HDPE plastic pipe. These non-machined serrations will not damage the plastic pipe surface and have a fused epoxy finish to protect against corrosive soil conditions. Installers prefer our Patented bell design which incorporates a cast-on half clamp and a detachable clamp, with our easy to install proven 2-Bolt system that saves valuable time and labor costs.