Steel does not necessarily indicate the same type of steel in two different items. Steel can take many forms, but stainless steel and carbon steel are the most common ones. There may be few differences between the two types, but one certainly has some distinctive characteristics.
Rhinox is a manufacturer of stainless steel plumbing fittings where all stainless steel products are designed to prevent oxidation. This product contains a minimum of 10.5% chromium by mass. In contrast to iron, chromium is not prone to oxidation. Because chromium does not rust or corrode when exposed to oxygen, it is an indispensable component of stainless steel pipe fittings. The iron content of stainless steel creates a barrier between atmospheric oxygen and the protective layer of chromium. This prevents corrosion of the metal.