Compression joint is a term typically used in construction. It's a bell and spigot joint that becomes watertight when the spigot is pressed into a compression gasket in the bell.

Compression joint is a term typically used in construction. It's a bell and spigot joint that becomes watertight when the spigot is pressed into a compression gasket in the bell.

Normally cast iron pipe one end in a HUB (BELL) and the other end plain to (Spigot)

The Spigot end is the ends that goes into the socket end of the pipe

RTR pipe is Reinforced Thermosetting Resin Pipe (RTRP) or fiberglass pipe. A Keylock joint is a restrained joint, nylon rods (keys) slip into groove on the spigot and in the bell of pipe and restrain the pipe from pulling apart. The rods (keys) are removable.