If you have spent any significant amount of time looking at cannabis content on the internet, then you have probably seen someone wearing a ring that doubles as a joint/roach holder/clip.
They are sold on Amazon as well as a number of other outlets. They seem to range between $10 and $15 dollars and come in packs of 4-6 rings.
Below is an embedded video review demonstrating what the rings are, what they look like, and how to use them courtesy of The Higher Things Club on YouTube: