A:AnswerMicrowave model PES7227SLSS is a countertop only installation and should not be installed built-in. Due to this, there is not a compatible trim kit available. - Julia@GEAppliances
A:AnswerI think it work if you glue a couple 3/4" wood shims on the top of the cutout for the anchor screws to grab. There will be a big gap on the top.