Product Focus: Radiant Heating Systems Issue: 9/01 Watts Heatway's Onix radiant tubing is designed for use in Staple-Up applications due to its flexibility and durability in construction and engineering. Onix is a highly polymerized, carbon-packed, Kevlar-reinforced rubber hose with an internal aluminum oxygen barrier. It is installed at very tight bend radii and doesn't kink. Onix won't be gouged or marred as the tubing is snaked through framing, and the location of the aluminum oxygen barrier inside the tubing protects it from damage.Watts Heatway.