Bass Rockers HR2503 4.5" (11.43cm) Screw-On Square Horn for Pro Audio PA DJ Tweeter Drivers Horn Measurements: Throat Diameter: 1" (25.4mm | 2.54cm) Cutout Size: 3-1/2" x 3-1/2" (89mm x 89mm | 8.9cm x 8.9cm) Distance between holes: 3-15/16" (100mm | 10cm) Distance between holes (diagonal): 5-9/16" (141mm | 14.1cm) Overall Width: 4-1/2" (114.3mm | 11.43cm) Overall Length: 4-1/2" (114.3mm | 11.43cm) Overall Depth: 3" (76.2mm | 7.62cm)