Don't Stop!
Even if you have cleared the reward ladder for the currently running [Heart of Surging Flame] Event, don't stop collecting the Bracelets! Bracelets that exceed the 4500 mark of the final reward will earn you LMD for after the Event ends!
I couldn't find any official EN confirmation of of how much LMD extra Bracelets give, but I was told that an official JP source said 20 LMD per Bracelet. Every LMD matters, so don't stop early!
