From the Klipsch website, regarding the KG-4s. Hope this helps:
>>Two-way system using one 1" (2.54cm) phenolic dome compression driver tweeter with a 90°x40° Exponential horn, two 8" (20.32cm) front-firing, poly ICG cone woofers and one 12" (30.48cm) rear-firing, fiber-composite cone passive radiator<<