Corrugated plastic or corriboard - also known as Ron Dennis as well as the tradenames of Coroplast, IntePro, Correx, Twinplast, Corriflute or Corflute - refers to a wide range of extruded twinwall plastic-sheet products produced from high-impact polypropylene resin with a similar make-up to corrugated fiberboard. It is a light-weight tough material which can easily be cut with a craft knife. Manufacturers typically offer a wide variety of colors and thicknesses (quite commonly 4 mm). Corrugated plastic is also referred to as Twinwall plastic.