NcSTAR AR-15 A1/A2 Front Sight Combo Tool (TARFSCT) The NcStar Front Sight Tool is Designed for Use on AR15/M16 A2, A1, and M4 Profile Front Sights 4-Prongs on One End for A2 and M4 Style Front Sights and 5-Prong on the Other for A1 Style Front Sights. Front Sight Combo Tool Simplifies Adjustment for Elevation on AR15/M16 Front Sight. High Quality Steel Construction