HOBSON-ZINGO Chain Quick Link Pliers
In theory and sometimes in practice, you can separate master links (for removing an old chain) by hand. The reality is sometimes a Will Smith slap in the face, and you’re there getting frustrated for fifteen minutes.
It’s worth that for one use, but in fact, will last a thousand times that many, at least. Another example of, “It doesn’t take a genius to buy Hobson-Zingo.”