Theater Solutions B1 Black Bookshelf Speakers Surround Sound Home Theater Speaker 2 Pair Pack Theater Solutions B1 home theater 2-way bookshelf speakers, recommended power is 10-200 watts per speaker, efficiency is 89dB, frequency response is 45Hz-22 kHz, 8ohm 2-way design and functionality, bi-laminate composite, balanced shielded woofers, ferro fluid cooled, titanium coated, balanced, shielded tweeters, 2,200Hz crossover frequency Rear port vents, spring loaded raw wire connections, non-resonant MDF enclosures with black wood grain finish, detachable black fabric grills, speaker size is (H x W x D) 9.5"  5.875"  6.25" Designed and engineered in the USA, these speakers require a home audio receiver or amplifier to power them Use for surround sound, center channel, home theater, multiple room system, industrial sound, bookshelf, this listing and price is for 2 pair / 4 indoor speakers