Good performing Altec-Lansing ACS-90 speakers. Two piece speaker system, excellent sound quality. The ACS-90 system includes two speakers. However, power is not a problem with this speaker as the amplifier, built into the base of the right-hand speaker, provides ample power for casual listening while you're sitting at your computer. The right-side speaker has front-mounted volume and treble controls. Speakers are 7 inches high. The connections on the ACS-90, all located on the back of the right-hand speaker, are straightforward. First of all, going from right to left, after the on-off switch.