FIT System - The FIT system eliminates measuring, cutting and trim for a perfect fit every time 2 ., 58 dBA (3.0 sones) at Low Speed - Keep noise down in the kitchen with the quiet operation of 68 dBA (6.4 sones) at the hood's highest speed with a recirculation option. 3, Hidden Vent, Powerful Variable-Speed, 225 CFM 4 Motor Class - Variable speeds provide the right amount of ventilation for every meal you prepare. 4 Based on vertical 7" round duct installation., Incandescent Lighting - Incandescent lighting makes it easy to see what you're cooking with bulbs that are inexpensive to replace.