Frame Material: ABS Plastic; Mesh Material: Cold Rolled SteelOuter Diameter: 139mm / 5.47 inch; Inner Diameter: 93mm / 3.66 inchScrew Hole Diameter: 4mm / 0.16 inch; Diagonal Center Hole Distance: 108mm / 4.25 inchDistribute screws, make you more convenient installation.Great for speaker cabinet, home speaker or speaker.
eBay