LevelOne KVM-0421 4-Port USB KVM Switch is 4-port Slim Desktop USB KVM Switch with audio and microphone switching function. The KVM switch allows users to access, control four USB-enabled computers from a single console. (Keyboard, Monitor, Mouse, and speaker set and microphone). It also offers user-programmable simultaneous/independent switching of PC channel and Audio/Mic channel for flexible multimedia application with KVM switching.