THE WORLD’S ONLY STAINLESS STEEL REGULATOR Beautifully machined. Beautiful performance. And it keeps the oceans beautiful, too. As the first “Green” regulator ever designed, the ST1 is made of a special grade of 316 Stainless Steel that is 100% recyclable. The ST1 offers superior corrosion-resistance and does not require Chrome or Nickel-plating processes that create environmental concerns.