Give the installation of your microwave a custom, built-in appearance by using a trim kit to hide the gap between the microwave and the cabinetry or wall. Trim kits are available in 27-in and 30-in widths. Microwaves can be installed alone or over a 30-in. single electric wall oven. 16.75-in. H x 25.5-28.5-in. W x 21 -n. D with flush mount receptacle or 22.75 D if non-flush receptacle is used.