The Dell Versa Rail was originally designed by Dell to be the fix all rail kits to work in all racks that do not support the Dell Rapid Rail kit. Unfortunately, this is not the case. The Dell Versa Rail is designed to only work with 4Post Racks that have a rack mounting depth of 27 1/2″-29″. The Versa Rail Kit will also only work in a 4Post rack that has round, non-threaded holes. This is due to the fact that the rail kits themselves have threaded holes. So, given the constraints, the Dell Versa Rails will not work with a large number of racks on the market.
Versa rails can also be installed into a square hole rack by using a Versa Rail Alignment Kit. Unlike cage nuts, the Versa Rail Alignment parts are thru hole, so 2 sets of threaded holes are not a concern.