Single duplex opening with finishing plate. Oversized plate covers flush plate and carpet edges. Finishing plate is 4 3/4 x 5 3/8 (121mm x 137mm). Flush plate is 3 7/8 x 4 5/8 (98mm x 117mm). NOTE: A minimum 1 1/2 preset or afterset is required on Pro Series Underfloor Duct to support standard duplex receptacles and communication devices when using flush activations. The 1 preset or afterset should be specified for pedestal style fittings or when cabling will be pulled through the activation point.