A Shower arm is best known to support a shower head.
A shower arm comes in two types; Plastic and metallic, the major difference is the material they are made of.
Both the plastic and metallic shower arm have a standard half inch connection.
The plastic arm connector has both female and male connector .
The plastic arm also hides cables hence making the connection neat.
The metallic connector has both ends as male hence it must use a socket for connection.