Improved Rangs is the first upgrade of Path 1 for the Boomerang Thrower in BTD6. It increases the Pierce of the Boomerang thrower to 8 (from 4). It can be unlocked for 100XP.
It was formerly named Multi-Target in previous games. However, Multi-Target allows 7 bloons to be popped from 3, while Improved Rangs allows 8 bloons to be popped from 4. It also costs less than in BTD5, with a cost of $170 on Easy, $200 on Medium, $215 on Hard, and $240 in Impoppable.