Say goodbye to Cage Nuts and start using the faster, easier way to mount your equipment in 19" racks. The revolutionary new RackstudsTM are a universal replacement for the common cage nut. If you use cage nuts to mount IT, Pro A/V, Security or Telecommunications equipment in 19" racks, you're going to love RackstudsTM. Suitable for most* 19" racks with square punched vertical rails, RackstudsTM go in from the front and provide you with a place to hang your equipment while spinning on the lock nut. This makes mounting even heavy equipment much easier; even if you're on your own. They are easier, faster and safer than cage nuts and very strong. *Ensure your rail thickness does not exceed 2.2mm/0.086". Some free-standing racks have thicker rails and this version will not fit. Use the new DARK blue RSL100-2.7 if your rails are thicker than2.2mm/0.086". http://www.amazon.com/dp/B00WFQB4DO