Originally used in premium speaker systems sold in the 90's and early 2000's, the Foster E100T10 8 ohm planar tweeter's low mass diaphragm is driven by a powerful motor for excellent transients, response up to 40,000 Hz, and high efficiency for it's size. With smooth response and low distortion, these NOS (new old stock) drivers will match the performance of current tweeters with similar design.