Physically prevent access to a USB Type A Port Quick and simple to use Pack of 10 Type A Blockers Single key & 4 blockers or individual keys are also available 2 Year Warranty USB Port Blockers are useful little devices that system administrators can use to physically prevent access to USB ports. USB Port Blockers allow locks to be inserted and removed from USB ports to stop unauthorised users from inserting pen drives, USB mass storage and mobile devices into shared workstations or devices with USB ports in public spaces. To use, simply attach a lock to the key and insert it into the USB port. Release the sliding mechanism on the key to leave the lock in place. To remove, simply insert the key back into the lock and pull away. Please note: these port blockers are only compatible with the corresponding colour of port blocker key This product is also available in other colours and configurations: Pink  40460 10 Pack Blue  40462 10 Pack White  40464 10 Pack Orange 40463 10 Pack Green  40451   4 Pack + Key Pink  40450   4 Pack + Key Blue  40462   4 Pack + Key Orange 40453   4 Pack + Key Green  40621  Single