Energy C-50 Bookshelf Speakers (Pair, Black) (Discontinued by Manufacturer) Pair of compact design on-wall or bookshelf speakers Each is equipped with a 4.5" composite fiberglas woofer and one 1" chambered aluminum dome tweeter Frequency response: 65Hz-20kHz +/- 3 dB May be wall mounted with the Energy Macromount(TM) bracket Included rubber bumpers for shelf standing