5-8% toughness on Chained Hit.
Hitting an enemy gives them 1-4 stacks of 2.5% Brittleness. Debuff lasts for 5 seconds and can have a maximum of 16 stacks.
20-35% Toughness on Elite Kill.
5-8% Strength every 0.4 seconds while aiming, stacking 5 times. Discharges all stacks upon firing.