If you are mounting a vinyl pergola or arbor to a wood deck or cement patio, the Pergola Bolt-Down Bracket System makes it easy. Simply measure your footprint and lag bolt the brackets into place. Insert 4 in. x 4 in. pressure treated wood posts (purchase 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 Oasis Pergola's Portland Pergola, Venetian Pergola, and Bellagio Pergola. The manufacturer highly recommends that if you installing any of these vinyl pergolas to a flat surface, that you purchase this kit. The mounting system comes with 4 brackets and all the necessary hardware. A drill is required for assembly, as well as 4 in. x 4 in. posts, which need to be purchased separately. Detailed instructions are included.