GE APPLIANCES JX15BUMPBB microwave accessories

We don't understand why this kit is required for 1.5 inch deep cabinets when we are using standard top vent option plus spacer kit for 36 inch wide opening. It will make our ZSA1202PSS model oven stick out much too far. It seems there is an extra vent above the front door, but it only appears to need an inch of space, which it would have.

We have a 15" depth cabinet above our stove without outside ventilation. Was very upset to learn that GE no longer made a front venting microwave (mw) when ours went out as all our other appliances are GE. So...we ordered the bump out kit which took almost a month to arrive. Tonight we installed it, and I'm not pleased at all. The mw sticks out 3" past our cabinets. That's 2" of metal on the top of the mw and 1" of the venting. I would have been better off adding pieces of sheetrock or wood behind the mw bracket that came with the mw, building it out 2", then having it protruding 3" in front of the cabinets. I may still, but also not crazy about adding even more holes to the above cabinet. Please bring back at least 1 model in front venting mw, this has been a needless headache!