This is a TROY Sight Tool known as the BattleSight, model ST00-ADJ-000T-00.
Easily adjust elevation on Troy Front M4 and HK Style BattleSights(TM) and windage on Troy Front and Rear BattleSights with Troy's BattleSight Adjustment Tool. Available in Black.
Features:
Made for Troy Front M4 and HK style BattleSights
Quickly adjust the sights on your rifle with this tool