Helium is an inert and non-flammable gas with high thermal conductivity, low molecular weight and size, and lowest boiling point known. It is also tasteless, odorless and colorless gas with purity reaches up to 99.9999%.
Helium is mostly used for welding purposes as it can create an inert atmosphere that prevents metals from oxidation. It is used in the manufacturing of semiconductors, neon tube lights and electronic lamps. Helium is used in diving as a breathing gas where it is mixed with oxygen, also as a medical anesthetic in some psychological cases. Because it is lighter than air, Helium is used to inflate balloons and airships.