Helium is a colourless, odourless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table.
While its most common use is in cryogenics, particularly in the cooling of superconducting magnets, with the main commercial application being in MRI scanners, it also has industrial uses as a pressurising and purge gas, and in processes such as growing crystals to make silicon wafers. However, balloons are perhaps the best known use of helium, even if the account for a very small fraction.
Helium can also function as a shielding gas in gas-tungsten arc welding where materials may be contaminated and weakened by air or nitrogen. Although Argon is a cheaper solution, Helium may be preferred for welding materials like aluminium and copper that have higher heat conductivity.