later These keystones are cheaper than other brands but you pay the price in a different way. I installed these keystones in a Cable Matters 24-Port Blank Rack Mount Patch Panel. The locking clips are very rigid and it is difficult to snap the keystones into place. My thumbs hurt after installing 24 keystones. The big problem is that even rigid clamps are brittle. Others have pointed out that you cannot remove Keystone without breaking the retaining clips. I actually broke three clips trying to *set* the capstone. Keystone appears to be working properly electrically. I have contacted the seller to see if they are honoring their warranty and will post an update. The supplier validated their warranty and sent me 5 spares to compensate for 3 connectors whose clips broke during installation. Because of this, I have also updated my rating to 4 stars.