Polk Audio FXi3 High Performance Surround Speakers (Pair, Black) Pair of surround speakers with butyl rubber surrounds for high performance durability. Equipped with one 5.25-inch dynamic balance polymer composite driver Features a neodynium magnet and a heat sink on the back of the magnet Equipped with one 1-inch silk/polymer composite dome tweeter Bi-Pole/Di-Pole switch conveniently located on front baffle