All ductile iron tapped caps have a FPT (female pipe thread) outlet. Gasket bell ends are designed to push on to IPS (iron pipe size) plastic pipe. The pipe end must be beveled and lubricated with gasket pipe lube before inserting into the gasket bell end. The vertical ears on the caps are designed to attach joint restraint products. The horizontal ears on the caps are designed to attach spigot end fittings such as SBR reducers or plugs.