It is not installed as yet, I have not opened up the box.  During the holidays it will get done by a family member.  The  labelling indicated 30" which is the standard size for most house stoves,  760 CFM, I chose because I do a lot of cooking so most of my burners are being used and sometimes the oven at the same time.  You would need a hood that can carry out smoke, heat, steam, grease, etc. from cooking out of the house which is to be installed under the cabinet and has a duct for the air to go outside.  Also I like the idea of the LED lights which will save on electricity so I can keep my lights on most of the time.