Capper will crimp the crowns on Beer and Champagne bottles.
The Emily capper features a magnet for holding the cap while crimping. Generally what most home brewers use.
The Super Agata capper is the next step up, for the true brewers... It is bench mountable, allowing for more stability. It also has an automatic height adjustment.
The Agata on the other hand is the perfect compromise between the Emily and the Super Agata, featuring bench mountable stability it is rear pin-set meaning you will have to manually change the height adjustment when switching between bottle sizes.