From The Heroes of Might and Magic III wiki

Class	Air Magic
Basic cost	8
Duration	1 round/Spell Power
Level	2nd

Target allied unit make ranged attacks as if had higher Attack rating.

Level	Effect
None	Attack incresed by 3
Basic	Cost reduced by 2
Advanced	Attack increased by 6
Expert	Affects all allied creatures

[edit] Heroes specializing in Precision

• Zubin the Battle Mage

1