Aiming down the sights increases damage. Upgrading it applies a healing effect every three consecutive hits and reduces scatter.

• Effect 1
  Lvl 1: Increases damage by 8% when aiming down sights
  Lvl 2: Increases damage by 10% when aiming down sights
  Lvl 3: Increases damage by 12% when aiming down sights
  Lvl 4: Increases damage by 14% when aiming down sights
  Lvl 5: Increases damage by 16% when aiming down sights
• Effect 2
  Lvl 1: Reduces scatter by 10%
  Lvl 2: Reduces scatter by 15%
  Lvl 3: Reduces scatter by 20%
  Lvl 4: Reduces scatter by 25%
• Effect 3
  Lvl 1: A sequence of 3 consecutive hits restores 10% of max structure points
  Lvl 2: A sequence of 3 consecutive hits restores 20% of max structure points