Ninth-City 3.5" Black Speaker Decorative Circle SubWoofer Grill Cover Guard Protector Mesh Inner diameter: 78mm/3.2inch.Outer diameter: 107mm/4.2inch. Two screw holes center spacing: 90mm Height: 8mm.Color: Black. DIY speaker grille, suitable for DIY speakers and cars speaker decorative circle. Distribute four screws, make you more convenient installation.