Accessory vent kit for WhisperLine series Includes: two 4-Inch double inlet grilles, two back draft dampers, two clamps, zip ties, and a 6- to 4-Inch Y-adapter Compatible with WhisperLine series In-Line Fans and FV-NLF04G WhisperLine 4-Inch Duct Inlet Grille Grille pattern: slotted with beveled edge and white finish Double inletBackdraft Damper: 2 (4) Clamp: 12 Grille Type: 6 - 4 Double Inlet Inlet Grille: 2 (4) Y-Adaptor: 1 (6 - 4 x 2)