These items are constructed in Aisi 420 Stainless Steel, as this grade is “a hard steel”, and favoured for quick-release coupler pins to prevent the balls of the quick-release coupler from damaging the surface of the pin and causing it to seize in the long run.
Note the option, Aisi 316, is more resistant to aggressive chemicals such as Chlorine, but as a “soft” Stainless, cannot be hardened.
As a result, please consider this series as food grade, and not resistant to aggressive fluids.