Improved-efficiency diaphragms & magnet structures; Carbon fiber injection-molded polypropylene cones; Treated woven cloth surrounds; 1" voice coils on aluminum formers; 1" flush-mount dome tweeters; System imp: 4ohm ; Quick-disconnect terminals; Freq resp: 65Hz-20kHz; Efficiency: 92dB @ 1W/1m; Mounting depth: 1.75"; Includes passive crossovers & speaker grilles;