I invented, and started selling, that chain breaker in 1973. The original one was for 35 chain, which they still make.
I'm surprised you haven't heard of it, I think all the better kart shops still sell it. If you're on a budget, it may b is are you are e too expensive for you. I sold the original one for $25, I'm sure it's more expensive now. Keep it hidden, a lot of people want to borrow it.
Oh, and by the way, it only works with the newer space chain, it won't work with the cheaper, commonly available, chain. The kind you get at the local hardware store.
I think they still call it space chain, it was a term we used when the wider space chain first came out.
Nice video.