J&S supply DIY Cabinet Flat Pack Kitchen M/W Base.A built-in microwave cabinet is an elegant way to free up counter space and give your kitchen a high-end, built-in appliance look. Our 24-inch microwave base cabinet carves out a convenient spot under your countertop – tucked out of sight but still within easy reach of everyone in the family. A built-in microwave cabinet is an elegant way to free up counter space and give your kitchen a high-end, built-in appliance look. Our 24-inch microwave base cabinet carves out a convenient spot under your countertop – tucked out of sight but still within easy reach of everyone in the family.