A:Answer Hey there, and thanks so much for your interest in our microwaves! We’re glad to advise. If you’re referring to models PVM9179FRDS, PVM9179DRBB and PVM9179BRTS, those models are very similar and the main difference would simply be the finish/appearance. The ‘black slate’ is a low-glosse matte, metallic paint finish on steel, the ‘black’ finish is also painted over metal, while the ‘black stainless’ is a shiny finish that is applied and infused to stainless steel using a variety of tested application procedures. We hope this information is helpful. If you have additional questions or concerns, or wanted to ask more about a specific model, we’re always happy to help here or over social media. All the best! -Sarah@GEA