Pokemon GO Premier Balls are exclusively used for catching a defeated Pokemon GO Raid Boss. The Better your raid party does the more chances you will have to catch the Raid Boss at the end.
Pokemon GO Premier Balls
|Description||These Pokeball’s are used only for catching Raid Bosses.|
|Obtaining it||You can obtain Premier Balls exclusively only from Raid Boss Battles|
“You’ll also receive a number of Premier Balls used for catching the Raid Boss. If Trainers on your Team made substantial progress in defeating the Boss, members of your Team will be rewarded with additional Premier Balls. You cannot use Great Balls or Ultra Balls here, you’ll only be able to use these Premier Pokeballs to catch the Boss Pokémon. However, you can use Berries to help capture this Pokémon. Aim carefully – once all of your Premier Balls run out, the Boss will flee.”