The VIK crown capper is the most advanced capper. It can clamp the crown cap on all types of beer bottles. Conveniently, a magnet holds the crown cap in the capper, so you won't push it off the top of the bottle. With the included adapters, you can also use it with the 29mm "champagne" crown in addition to the 26mm crown glass.
This video will help you to use it: