How do colocation server cabinets differ from server racks?

A typical server rack is designed to house a range of equipment within the rack which has secured front and back doors. A colocation server cabinet has 2, 3 or 4 bays each of which is secured with a lock and key, or access controlled (card or biometric) to provide a highly secure enclosure into which to place different clients equipment. A colocation server cabinet is ideal in shared server rooms or data centre spaces with multiple client servers, storage and IT network devices.