wall cap considerations for range hood
I have a microwave/range hood combo in my kitchen that was here when I bought the place. I did some reading and see that it can be converted from recirculating (worthless) to outside venting (yay). The unit is mounted on an exterior wall and it seems that the spot for the vent duct is between studs (yay again).
So my question is what is the best type of cap (is that the right name?) for the outside of the duct? The unit is designed for a 3 1/4" x 10" duct.
I looked around at my local box store (Home Depot) and they seemed confused about what I was asking for and when I finally found something I was worried because there is no screen or anything over the outside part. Seems like an invitation for birds nests or other things coming back in. Also the backdraft damper (or flap or whatever it is called) seemed marginal at best.