Hi - A trim kit is not available for model JES1657SMSS. This model is intended for countertop use.
We suggest our GE Profile™ Series 2.2 Cu. Ft. Built-In Sensor Microwave Oven
PEB7227SLSS. It is compatible with GE® Required 27" Built-In Trim Kit JX7227SLSS and GE® Required 30" Built-In Trim Kit JX7230SLSS. We encourage you to view the Quick Specs for cabinet cutout dimensions: http://products.geappliances.com/MarketingObjectRetrieval/Dispatcher?RequestType=PDF&Name=PEB7227SL_BL_R2_17.pdf - View all BUILT-IN MICROWAVE OVENS: http://products.geappliances.com/appliance/gea-category/microwave-ovens?TYPE=Built-In - Keep in touch! SUE@GEA