Product review (5 stars): Excellent Solid Dryer Vent
I used this product for a new drier vent run. After boring/hammering a ~4" hole through cinder block and brick, I used mortar caulk to center and seal the 4" metal duct within the hole leaving 1/2" protruding to fit tightly into the base of the Vent Closure. The plastic unit is light weight but solid and well finished. I wiped the surface with thinner and primed all exposed portions with a flat red primer. The paint took very well and there were no blemishes visible on the vent. The bottom unit was silicon caulked around the mating to the duct and attached to the brick with four 3/16 Tapcon screws&nbsp;<a data-hook="product-link-linked" class="a-link-normal" href="/Red-Head-HW4-134-Tapcon-Hex-Washer-Head-1-4-Inch-by-1-3-4-Inch-Anchor-100-per-Box/dp/B002WGJSFI/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">Red Head HW4-134 Tapcon Hex Washer Head 1/4-Inch by 1-3/4-Inch Anchor (100 per Box)</a>&nbsp;providing a tight, flat, level mounting. The upper unit seated squarely on the base and solidly mounted as well with two additional screws. The whole thing is very secure, operates quietly, and closes tight when not venting. Excellent thermal isolation - the duct at one-foot inside the basement was at the ambient basement temperature while it was below 40 degrees outdoors. The instruction sheet includes a number to call for some sort of tensioning spring if you intend to use this for a non-drier installation (range hood or down-draft cook top?) but I did not need it for my installation. A photo of the installed unit is posted above.