The Bolt Down Bracket System enables Vita pergola owners to mount their pergola safely and securely to a wood deck or cement patio. Simply measure your footprint and bolt the galvanized steel brackets into place. Insert 4 x 4 (10cm X 10cm) pressure-treated wood posts (purchased separately) into the brackets and screw them in place. Slide your pergola posts over the wood posts, and screw the pergola posts into the wood. The result is a lasting installation that is safe and rigid. This mounting system was specifically designed for Vita brand pergolas. We highly recommend that if you are installing any of these vinyl pergolas on a flat surface, you purchase this kit. The mounting system comes with brackets and 1.5” (3.8cm) self-tapping screws. The Bolt Down Brackets are guaranteed under a limited 5-year warranty against manufacturing defects. Important Note: DO NOT use the bolt-down bracket system for installing the pergola over concrete pavers, patio stones, or interlocking bricks.