Many times I've needed a good counterweight for boom stands for mics, especially pairs of them on a stereo bar, and it's hard to find something satisfactory. The usual problem is finding a convenient and safe way to attach or remove them. I've seen people try to improvise something and usually it's a safety hazard. But finally here is a design that solves those problems.
The bright orange colour is good for hi-viz but I can't see how that's helpful on the end of a boom, so I'll probably spray mine black. I'm just glad it's easy to take on and off the boom, and is safe and secure.