There are variety of small plumbing fittings made of brass, copper, plastic and chrome in the hardware market.
Copper fittings refer to the products used in pipes in the supply of hot and cold water or central heating. Copper fittings come in a number of different shapes and sizes, but they are generally classified into four groups according to the actual method the copper fittings use to be put into the pipe.
The first group is known as solder ring copper fittings. This kind fitting contains a small ring of cooled solder around the circumference of the inside of the fitting. When the copper pipe is pushed into the copper fitting and flux is applied along with intense heat, the solder melts and runs around the joint, cooling and solidifying once more as soon as the heat source is removed, forming a solid joint.
The second group of copper fittings is known as end feed fittings. These fittings are almost identical to solder ring fittings except that they do not contain an integral ring of solder. When using end feed copper fittings the solder is supplied by the plumber from a reel or solder stick. When the copper fitting joint is at the correct temperature, the plumber offers the tip of the solder reel or stick up to the joint. The intense heat melts the solder. Once more the joint is made when the heat is removed and the solder sets. These copper fittings are favored by plumbers as they are considerably less expensive than solder ring fittings, and equally efficient when used correctly.