StarTech.com 4 Port Professional VGA USB KVM Switch with Hub - 1U Rack-mountable KVM Switch (SV431USB) - KVM switch - 4 ports

Control up to 4 PC or Mac computers from a single keyboard, mouse and monitor and share any USB device between all connected computers. The SV431USB 4 Port rack mountable VGA USB KVM Switch with Hub offers simple control of up to four computers from a single monitor/display and USB peripheral set (keyboard, mouse).
The USB KVM switch features an integrated 4 port USB hub, allowing you to share connected USB peripherals between the four controlled PC/Mac computers as though the devices were connected directly.
Offering convenient placement and installation options, the KVM switch features a 1U rack-mountable form factor and rear port connection to master and slave computers, allowing you to make the necessary device connections without disrupting your workspace.
A cross-platform solution, the KVM switch supports high resolution applications at up to 1920x1440 and provides a smooth operating experience when controlling mixed (Windows/Mac OS/Linux) environments.
If you'd like to mount this KVM switch to your server rack, StarTech.com offers a 1U Rackmount Bracket (sold separately) that turns this KVM into a rackmountable KVM.