Serious performance, natural sound, great reliability at an exceptional value; Bookshelf speaker configuration for full range sound in any application; Designed for use as front main or home theater surround speakers (External Amplifier Required) Engineered MDF wood construction to reduce cabinet resonance; Ultra high-end Neodymium tweeters provide accurate high frequency response; Ferro-fluid cooled tweeter for longer life Butyl rubber surrounds for increased durability and performance; Tuned bass port for controlled low frequency response and improved efficiency; 5-way gold plated binding post terminals for optimum conductivity Banana plug and speaker wire compatible connectors on all speakers; Low diffraction flush fit removable front grilles for spacious imaging; Magnetically shielded to avoid interference with other video products Premium crossovers feature Butterworth design for audio equalization; 18 gauge internal lead wire to reduce signal degradation