The Timbertech Azek Fusionloc Collated hidden Fastening system is designed to cover up to 225 square feet with its rectangular shape and #8 screw size. Made with stainless steel mandrel material and a Birch finish, this system features an open end type and flat head style for secure and efficient fastening. With one hole per leaf, this fastening system from TimberTech is an ideal choice for home improvement and building projects requiring hidden fastening solutions.