For all 8" In-Ceiling Models Metal straps span 24" on centers Remove plastic seal when speaker is installed Versatile and Inexpensive Dome / mounting flange slides along straps for positioning at any point between members Dome shields speaker from insulation Mouth Opening: 8-5/8" round Mounting Depth: 7-3/4" deep (works in 2 x 8 construction) Sold and shipped in pairs Lifetime Limited Warranty