Flexible line fittings--also known as water supply hoses--are hoses that supply water from the shutoff valve on the end of the water line to either the sink faucet or toilet tank. Flexible hoses also connect the hot/cold water lines to the nipples on the tops of water heaters.
Metal Braided Water Supply Hose
These hoses have an inner rubber tube with a braided metal outer covering that is flexible and moves freely as the inner hose is bent to accommodate the installation process. The metal is usually stainless steel so that any contact with water will not affect the braid.
Plastic Braided Water Supply Hose
The plastic braided water hose is similar to the metal braided hose, but has a plastic breaded outer covering along the length of the hose. With both metal and plastic braided hoses, the hose ends have nuts of various sizes (1/4-, 3/8- and 3/4-inch) to accommodate the various sizes of inlets on sink faucets and shutoff valves.
Toilet Water Supply Hose
Toilet hoses can have either metal or plastic outer braiding, but with one end of the hose having a plastic wing nut that fits onto the threaded inlet on the bottom of the toilet tank. The wing nut has an inner rubber seal that when screwed by hand onto the toilet tank inlet, produces a watertight seal.
Copper Water Hose
The copper water hose is made up of a hollow corrugated copper tube, with a brass nut attached at each end (as is the case with the sink/shutoff valve hoses, the nuts come in different sizes). These hoses are used to join water heaters to either the cold inlet supply line, or the hot outlet supply line.