+1 to Maximum Endurance Charges
25% chance that if you would gain Endurance Charges, you instead gain up to your maximum number of Endurance Charges
Gain an Endurance Charge every second if you've been Hit Recently 
Unflinching is a Notable Ascendancy passive skill for the Juggernaut that grants an additional maximum endurance charge, a chance to gain an endurance charge when hit, and generates an endurance charge every second if you were hit in the past 4 seconds. Additionally, whenever you gain an endurance charge, there is a chance it sets your number of endurance charges to its maximum.