Getting your brew into the bottle is pretty easy, but then you need to close it up so it can age nicely for a few months. A 12-ounce beer bottle makes a nice drink for two, and to close that up you need a capping tool.
Capping tools come in different sizes and prices. The style below has lasted us through capping hundreds of bottles, and it still going strong. It requires only one hand to operate the capper, leaving the other hand free to hold your bottle.
A few years ago, this would have been “necessary” but now, with a growing availability of self-capping bottles (which we use in the deluxe kits), a capping tool isn’t quite as critical as it once was.