Supertweeter with 3.15-inch cut-out. Horn used on APT:50 driver. No loudspeaker system or musical performance is complete without high-quality, durable HF devices, well-designed horns, and high-performance crossovers. Developed for totally Eminence loaded cabinets, or as upgrades to an existing device, Eminence HF drivers achieve extraordinary levels of audio performance with the same unrivaled durability you demand from Eminence bass and mid-range transducers.