This is a simple protective endcap for a rod measuring 7.8mm in diameter when printing from a rigid material. If you print from a flexible material, it should stretch to accomodate an 8mm rod with some force. I sketched this up to cap off an exposed metal rod end on a Christmas Stocking holder we have set up (since we dont have a fireplace). I printed it out of TPU to provide some protection in the unlikely event that someone bumps in to it.