Gypsum Channels – Gypsteel ULTRA® is made of special high-performance steel that undergoes stringent quality checks and controls to ensure correct and consistent base material for further profiling. The steel comes in rolled coils to maintain the proper thickness throughout its length. Quality checks ensure correct selection of material for strength and corrosion resistance. The steel sheet is work-hardened by passing it through a teethed roller with a patented design from Hadley which gives a typical unique knurling pattern on the surface. This knurling pattern is a key identifier of genuine Gypsteel ULTRA® from Gyproc.