DS18 PRO-HT1 PRO 4.5″ Twist on Slim Horn for Drivers with 1″ Throat DS18’s PRO-HT1 is the best way to boost the range, volume, and feel of the sound reproduced by your compression drivers! The PRO-HT1’s high strength ABS plastic casing ensures this horn can withstand the most demanding applications. The PRO-HT1 features a short throat with a 1″ diameter, allowing for crazy loud sound from your drivers. The circular profile and 110-degree coverage make this horn perfect for those looking to create a directional sound that will blow the competition away