Direct Vent Pro Collection 5" x 8" Inner Diameter Galvanized Vinyl Siding Standoff The Direct Vent Pro 5" x 8" Inner Diameter Galvanized Vinyl Siding Standoff is a component that is used in a typical venting installation. Use as a heat shield on structures with vinyl siding, or other temperature sensitive materials, to help prevent warping and or melting of the material. Use only on horizontal terminations and on any irregular surfaced siding (I. e. : ship lap siding, shake shingle siding) so cap is not imbedded in the siding. Sized for Square Horizontal Cap. Features: Inner Diameter: 5" x 8" Outer Dimensions: 19-7/8" x 19-7/8" Inner Dimensions: 15-3/4" x 15-3/4" Depth: 1-7/8" Use as a Heat Shield on Structures with Vinyl Siding Use Only on Horizontal Terminations and Any Irregular Surfaced Siding Sized for Square Horizontal Cap Direct Vent Pro features tight inner connections for superb performance, with no gaskets or sealants required (unless specified by the appliance manufacturer). All black pipe lengths, pipe extensions, and elbows feature laser-welded outer wall seams for a sleek finish. Low-profile locks and no hems or beads allow for a beautiful product that looks elegant in any interior. Direct Vent Pro is a unitized, coaxial venting system designed for use with direct vent gas or propane stoves, heaters, and fireplaces. Looking for Simpson Dura-Vent? You found it! Simpson Dura-Vent has changed their name to DuraVent. DuraVent is a recognized technological leader in the venting industry. Consistently the first to market with new innovations in venting systems, DuraVent has captured a leadership position in emerging markets. DuraVent has patents for several products and continues to design safe and technologically advanced venting. The company' s research into solving problems with corrosion, when biofuels such as corn are used, led to the break-through patent for Pellet Vent Pro