Straight Pipe Threads ~ A special kind of straight thread used only on iron pipe, toilet, and faucet fittings. A cone seal or gasket is usually included because straight threads will not form a complete seal without a gasket of some kind.
Wye ~ A Y-shaped fitting with three openings used to create branch lines. Allows one pipe to be joined to another at a 45 degree angle.
Piezo Switch ~ The electronic switch the bather uses to control the whirlpool and optional heater. This switch, based upon the piezo-electric effect, generates a voltage when pressure is applied to it.
Paul McElrath - Plastic Piping: Urinal ~ A plumbing fixture which receives only liquid body waste and conveys the waste through a trap seal into a gravity drainage system.