Selenium HM25-25 1" Exponential Horn 90x60 1-3/8"-18 TPI * Nominal dispersion: 90° H x 60° V Throat diameter: 1.0" Mounting type: 1-3/8"-18 TPI Dimensions: 10.79" W x 6.46" H x 5.94" D Cabinet cutout: 4-5/8" H x 9-1/4" W Selenium #HM25-25. * Horn type: Exponential Minimum frequency: 1,200 Hz