WPS SIDING SYSTEMS Featuring a unique and proprietary non-progressive attachment system, WPS can integrate solid phenolic, high pressure laminates, glass, porcelain, metal, acoustic, and radius panels into one substructure. HORIZONTAL FLUSH SIDING . Reveal: 3/16 . Can be utilized with phenolic, glass, and fiberglass panels . Non-progressive attachment system . Hybrid, Z-Clip, and