Hiviz ARN101 AR Vertical Tritium Front Sight Black Post for AR-15/M4

The Hiviz ARN101 AR Vertical Tritium Front Sight Post is a drop-in upgrade that brings 24-hour illumination to your rifle's existing front sight tower. Designed to fit most AR-15 and M4 rifles equipped with the standard A-Frame or folding front sight base, this replacement post installs in place of the factory sight blade and is locked in place with the included detent and adjustment tool.

Inside the post, a self-contained tritium element delivers bright, fully encapsulated illumination that does not rely on ambient light, so you can confirm your front sight picture in low light and at night without batteries or fiber-optic light gathering. The green tritium vial provides the most visible color option in dark conditions and is widely favored for defensive and service-rifle applications.

The post itself is molded from lightweight polymer to keep weight over the bore to a minimum and is finished in matte black to match the rifle. Its vertical profile is dimensioned for a standard sight picture, so no additional sight adjustments are required beyond seating the post and securing the detent spring.

Built by Hiviz as part of their tritium AR sight line, the ARN101 is a simple, reliable way to add nighttime aiming capability to any AR-platform rifle already wearing a compatible front sight tower.