Product review (3 stars): About As Good As It Gets For Now But Still Something To "Vent" About
Broan makes quality ventilation accessories and is a U.S. based manufacturer.  This is a popular and well-rated roof cap with pluses and minuses. If you heed the warnings and make the necessary adjustments relative to installation you should have a roof cap that provides trouble-free performance for years.

PROS:

1. A reasonably well-manufactured residential low-profile roof cap made from 24 gauge CRCQ  galvanized steel (frame).and aluminum internal sub-parts.
2. Black electrically-bonded epoxy finish
3. Integral back-draft damper and bird screen
4. Clear and relatively straightforward installation instructions.

CONS:

1. This roof cap is actually an import but cleverly and prominently depicts the politically-correct USA logo on its box. If you have an electron microscope, you will see that the item is actually a hybrid product globally sourced. The manufacturer does not provide details as to which parts are manufactured in the US.
2. This item should be supplied with the proprietary 4" DC4 duct collar necessary for proper installation, but you need to purchase this separately ($6.61) or purchase the RVK1A Roof Ducting "Kit"  which supplies all you should need for the job-two tie wraps,8' of 4" diameter flexible foil duct transition hose, the duct collar and a strip of self-sticking compression-type weather-seal.
3. The "bird screen" is simply a loose-fitting light gauge wire screen which can and will be penetrated by some birds and most definitely by ambitious squirrels searching for safe harbor, moisture and nesting. This screen should have been heavier gauge and screwed into the cap frame on all four sides.

RECOMMENDATIONS:

1. Still one of the better residential roof caps on the market at this time.
2. If you purchase the Broan kit (cited above) DO NOT USE the 8' compression duct hose. In most municipalities and townships, this is clearly not compliant with fire codes and regulations and will also trap more lint in the inner lining of the hose restricting air flow and creating a potential hazard. Instead, purchase a semi-rigid 4-8' section of smooth fire-rated aluminum duct available at most big box hardware stores and certainly any roofing supply outlet.
3. Skip the cheap tie-wraps furnished in the Broan kit if you purchased this-They are flimsy and do not yield a tight and secure grip on each duct junction. Buy two 4-5" stainless steel adjustable clamps.
3. Prior to installation, be certain to insure that the duct collar is properly installed into the roof cap aperture (opening). To do this, you will need to seat the seal with a good caliber roofing cement and seal all nails with this compound as well to assure water-resistance.