4 Pair 199 uF Bass Blockers 200Hz - 4 Ohm / 100Hz - 8 Ohm 6"x9" 6"x8" 5"x7" Bass Blockers BB-199 Removes sounds that are below a certain frequency Frequencies Blocked: 4 Ohms: 0-200 Hz and up / 8 Ohms: 0-100 Hz and up Designed to enhance the performance and power handling of tweeters and midrange speakers by removing frequencies beyond their capabilities Easily handles power of up to 50 watts