League of Legends Reforged Rune: Lethal Tempo

Basic attacks on-attack against enemy champions grant a stack for 6 seconds, refreshing on subsequent attacks and stacking up to 6 times. Gain [10−15% for Melee | 4−9% for Ranged) bonus attack speed for each stack, up to [60-90% for Melee | 24−54% for Ranged] at maximum stacks (depending on level), at which you also gain 50 bonus attack range and increase the attack speed cap to 10.