While making this video I forgot to mention what the name of the stainless steel block and it seems that no one wants it read all the posts below where I have answered this for everyone so I'm going to answer it here again. It has 2 different names, one is a doming block, the other is a dapping block. You can get it a harbor freight tools or Amazon.com. Try to but it in 3" and no smaller than 2 1/2". It also comes with or without the round head punches depending on how much you want to spend. I have another video to show you how to use it to round over your rings at    • Coin Rings...How To Round Over The Ends.  . I hope this answers the question because I've answered it below more than a dozen times now. Thanks and have fun at making yours.