StarTech.com 5-Pack 1U Vertical Cable Management D-Ring Hooks, Server Rack Cable Management, Cable Manager, Network Rack Wire Organizers - 5-pack 1U vertical cable management hooks for 19" server rack; Organize cables/reduce strain/improve airflow - Steel D-ring w/ 0.4in (11mm) opening - Use for lacing points for cable ties - Wire manager for patch panels/servers/switches/NAS/PDUs: