Product review (4 stars): Works great for my RV
Installed this on my fifth wheel.  Simple installation, hardest part is drilling the hole through the exterior wall.  At least mine had a mark to place the hole.  You will need a 4" hole saw, unless you want to live dangerously and use a reciprocating saw.

If using in an RV or anywhere with a small laundry closet, I recommend using&nbsp;<a data-hook="product-link-linked" class="a-link-normal" href="/Westland-VI490D-90-Degree-Vent-Elbow/dp/B003VAXC4M/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">Westland VI490D 90 Degree Vent Elbow</a>&nbsp;(or similar) to make the last turn.  Also easy to install, actually makes the entire thing easier if you're in a tight space.