Hello all! Just got my second customer calling in about needing a charcoal filter for their over the range microwave - that did not need it. I thought it was worth sharing this information. When you buy an over the range microwave (OTR) of any brand - they come able to be vented inside the home or outside the home. If you choose to install so it vents inside the home, because you do not have the ability to vent outside, that is when you would choose to add a charcoal filter to your microwave. This filter is for odor extraction only - not for the grease.. those are the shiny metal filters that came with the machine. If you turn on the fan and the air blows back inside the house you are vented inside. If you turn on the fan and its does not, you are vented outside. Years ago the manufacturers included both grease filters and charcoal in the box when you bought your microwave. Most Canadians do not read their manuals and put in all the filters. Now- if you think you need the charcoal filter just see if maybe it was put there in error and is not needed after all. I will not sell you a part, but I will make a new friend. This is why you call us when you need a part so we can chat and qualify your needs. Ordering online puts all the onus on you the customer to know what it is you really need. Let's work together. FYI Charcoal filters must be replaced every six months or sooner, depending on frequency of use. To be effective in odor extraction. There are many you tube videos showing you how to reverse the direction of the air flow (would have been in your initial instructions as well)