Limit Break

Star Limit Break
Limit Breaking your ships gives them a stat bonus, new and improved personal traits as well as Class Specific Buffs. Limit Break is available from the ship menu, you will need levels, coins, and dupes to limit break. It takes a total of 8 copies of unit to Max Limit Break (1 original and 7 dupes for LB)

Limit Breaking Bonus
Limit broken ships will get their base trait upgraded (Depends on the ship) and new class specific bonus unlocked. Those bonuses are :

Level Limit Break
Ships can have their maximum level increased from 80 to 85 when they hit level 80. Stat gains are also higher from 81 to 85. A total of 12 Oath Chips (オースチップ) of the proper type (battlecruiser/carrier/cruiser/destroyer) is required. Oath Chips can be obtained by trading in daily crystals, or as a rare drop on 7-2 (carrier) and N7-2 (cruiser)