This is standard sized Vernet Thumb Tip that’s been specially stretched to take large rings or coins, as used by Dave Bonsall in his famous ring routine where he vanishes up to 3 borrowed rings. You can also use it to vanish large coins, teaspoons and even a Sharpie!
You can make one yourself by heating up a thumb tip and stretching it out, but be warned, not all thumb tips will survive the process and it may take many attempts. See the video for performance and explanation. Used correctly, many magicians are fooled by this!