Rational 60.76.173 UltraVent Plus Combi-Duo (6-1/1, 10-1/1)Rational 60. 76. 173 UltraVent Plus Combi Duo (6 1 1, 10 1 1) Thanks to its condensation technology, the UltraVent Plus captures escaping steam and vapors. It's also equipped with special filter technology that reduces annoying smoke, such as that produced by grilling or frying. This recirculation hood doesn't require an external connection or the extension of an existing exhaust system. The hood is easy to install and can be retrofitted at any time.