The Duel Orb is the item used to get standard duelists to appear immediately in Yu-Gi-Oh Duel Links. Usually standard duelists takes 30 minutes after they are defeated to show up again. By using the item, players can earn EXP, golds, and rewards faster.
Boosted Duel Orb
The Boosted Duel Orb has a different effect from the Duel Orb. It calls standard duelists and they stay for 60 minutes right after the item is purchased. It is unavailable in the Beta version.
How to Get
Missions & Login Bonus
The Duel Orb is basically obtained by completing missions and as rewards for login bonus. Since other ways are not confirmed, the item is very valuable.
The Boosted Duel Orb is not available in the Beta, but will be purchasable in the in-app shop.
How to Use
Tap Top-Left Corner
Duel orbs can be used by tapping the top-left corner of the screen.
Effective Ways to Use
Players can get standard duelists to back to Duel World by the max number. That means it it the best to activate the orb when no standard duelists are availabe.
Since the max number of standard duelists become higher as the game progress, keeping the item at the early stage is recommended.
The Boosted Duel Orb should be used when players can play for 60 minutes.
I believe what it means is that for 60 minutes after you use the orb, the maximum number of duelists will remain in your world. Once the 60 minutes as passed, each Standard duelist you beat will again have a 30 minute respawn timer.
I have not tested this yet though, because i am saving all of my orbs for the toon event to max out on stars.