Product review (1 stars): Do not waste your money.
Useless junk. This product is described as adjustable - 0 to 18 in, suggesting that user could adjust this. It is not the case. This is NOT adjustable. Adjustable means that you can extend and retract, this product is adjustable only by - cutting. Typical marketing crap. There are much better designs, do yourself a favour and do not waste you money.

If you manage somehow to install it - and that is truly a challenge, be aware that this product, is actually dangerous - since there is an attempt to create air flow diverts with 2 small peace that are not secured and without any effort they could close inlet/outlet and therefore create a fire hazard. You are better off to remove them, or secure them with Al-tape. If left as received - it is only matter of time before you will be dealing with much bigger problem.

Furthermore, you will have to deal with air leak on every corner of this product, and to tape entire sides hoping to stop some of that air leak. Whilpool, this would be better designed by 3 year old.