Stormrazor

Stats

Values as the League of Legends Wiki's item data lists them, for every mode; the data doesn't state their units.

Effects

• Energized (unique): Moving and basic attacking generates Energize stacks, up to 100.
• Bolt (unique): When fully Energized, your next basic attack deals 100 bonus magic damage on-hit and grants you 45% bonus movement speed for 1.5 seconds.³

Movement speed duration changed to 2s in patch 26.11 (was 1.5s)⁴

Arena changes

• Attack damage changed to 50.
• Attack speed changed to 20%.
• Energized stacks per basic attack changed to 12.
• Energized stacks per 24 units travelled changed to 2.⁵

• Stormrazor and Phantom Dancer are recommended as first choices for a build using Fan the Hammer and Tap Dancer, with near 100% critical strike chance.⁶

• Stormrazor’s Energized effect builds stacks as you move and basic attack, up to 100. In Arena, each basic attack grants 12 stacks and each 24 units travelled grants 2 stacks.³⁵
• At 100 stacks, your next basic attack deals 100–250 bonus magic damage on-hit and grants bonus movement speed for 2 seconds. Since patch 26.11, the damage scales from 100 to 250 and the movement speed lasts 2 seconds.³⁴

Since patch 26.11, ability damage can trigger Stormrazor without first triggering it with an attack.⁷