The Panasonic PC-NLF64D WhisperLine Installation Kit allows you to install your bathroom fan with all the components readily available. It is a double pick up accessory kit that inclues (2) 4-inch double inlet grilles, two back draft dampers, two clamps, zip ties, and a 6"-4" Y-adapter. The entire kit is composed with 24-30 gauge aluminum. The PC-NLF64D Whisperline Accessory Kit is compatible for use with the Panasonic WhisperLine series In-Line Fans. The Panasonic PC-NLF64D WhisperLine Installation Kit is backed by Panasonic's 3-year manufacturer warranty.