I tried the first run "beta" Kolokol begleri, and they have been incredible. The shape and size is ideal. I got the copper composite. It has a very nice weight to it, enhanced by the bead. I think it's ingenuous that the bead fits into the cover, opening up potential for dialing in exactly the right weight. This fits with the kind of innovation I appreciate from Mellow Block. These have found their way into my pocket many, many times since arriving. I'm sure they will be regular slings for a long time to come.
