MONEL FITTING

https://www.nickelalloytubes.com/products/monel-pipe-tube-fitting.html

Monel is a group of nickel (from 52% to 67%) and copper alloys, with small amounts of iron, manganese, carbon, and silicon. Monel is not cupronickel as it has less than 60% copper, which makes it an expensive alloy. Thus, just like the use of Monel flange, the uses of Monel tube fittings are also limited to those applications that cannot be replaced by cheaper alternatives.

MONEL TUBE FITTINGS PROVIDED BY YUHONG
Monel pipe fittings are well known for its corrosion-strong and rust-resistant. They are resistant to corrosion and acids, and some alloys can withstand a fire in pure oxygen.