KEF R100 Bookshelf Loudspeaker - High Gloss Piano Black (Pair) The R100 features a 5.25 inch Uni-Q driver array, which consists of both mid-and-high-frequency drivers. The purpose of the array is to have both frequencies coming from the same place, allowing them to integrate perfectly and create a convincingly natural sound. Surrounding the Uni-Q driver array is our new mid-range Z-flex surround, which projects audio more efficiently into your listening space and results in undistorted high frequencies. The R100 affords you the option to use either a single amplifier as your source, or to bring in a second amplifier to handle certain frequencies. At just under 1 foot tall and 7 inches wide, the R100 is the perfect candidate for any bookshelf, desktop, or countertop in your home or office. The R100 bookshelf speaker comes in Gloss White, High Gloss Piano Black, Rosewood, or Walnut. No matter which finish you choose, youll also get a black grill for the face of the speaker.