MarvelMute Sound Isolation Clips - Resilient Sound Clips for Soundproofing Resilient Channel - Mounting Screws Included - Pack of 50 Clips

These are super handy for building sound insulation panels, because they require an air gap to really work well. These make it very easy, they're spaced correctly and everything. You just use them to divide the layers and it sets you up perfectly. They probably have utility in other types of insulation, but I can only speak to what I used them for.