What RoyB is showing is called smurf tube...or the trade name is ENT. Works great, just make sure you get the correct connectors for the smurf tube you are picking up...run a pull string through the tube will help in running wires..a string/twine with a sandwich bag tied on the end (makes a parachute-or called a mouse) suck it in with a vacuum cleaner...trade secrete...not really, but works and you don't have to fight pushing in the wires...or you can get the smurf tube with a pull string already attached...just make sure when you cut it you don't loose the line inside.