"S" system is used by many European breweries, also known as European Sankey. Distinguished by it's longer, narrower probe than the D System. It is used by breweries such as Heineken, Becks, Amstel Light, and Pilsner Urquell. The keg coupler connects to the keg valve, "tapping" the keg. Both the gas line from the CO2 tank / regulator and the beer hose to the beer faucet attach to the coupler.
Beer Keg Tap Features:
Stainless Steel body improves durability and resistance to chemicals
Stainless Steel handle fork for added strength
Tin-nickel plated probe is resistant chemicals and won't chip like chrome
Short handle is ideal for the smaller diameter 1/6 kegs
(Is my coupler a domestic or European tap? Here's how to check. With the handle raised, look at the bottom of the tap. Does the metal prod extend past the bottom of the coupler? If yes, it is a European tap. If the prod is even with the bottom of the tap, it is a domestic tap.)