Selenium HM25-25 1-Inch Exponential Horn 90x60 1-3/8-Inch-18 TPI Selenium HM25-25 1" Exponential Horn 90x60 1-3/8"-18 TPI 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. Selenium HM25-25 1" Exponential Horn 90x60 1-3/8"-18 TPI Horn type: Exponential Minimum frequency: 1,200 Hz 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.