Check the listing for details. BUILDER'S BEST 110696 Saf-T-Duct Dryer Outlet Box. Color: White, Condition: New. Listed at 46.25 USD. The Saf-T-Duct Dryer Outlet Box from Builder's Best finishes off dryer vent rough-ins and easily adds or recaptures space in the wall behind your dryer for venting. The unit can be used in-wall (prior to drywall) or on-wall (after drywall is installed). The standard 4 in. round connections allow for the best airflow and connect easier than ovals. • Fits all 16" centers 2" x 4" & 2" x 6" • 6 prescored true 4" dia knockouts in most common positions • 6 starburst knockouts for gas connections & venting • Plastic meets UL standard 94HB tests for flammability • Self-trimming unit 18"W x 24"H • White Includes: 1 dryer outlet box Product Dimensions: 4.562 x 18.062 x 24.125 in., 2.12 lbs. Package Dimensions: 25.1 x 19.1 x 4.8 in., 3 lbs.