One of the most popular, the Blackjack ACE Flashlight Holder is designed to fit round “Tactical” style lights. It's a helmet flashlight mount that also fits the Pelican M6, 2330, and 2300 series lights. The Ace also works great with the Surefire G2, G2D, G3D, G2L, G3L, 6P, 9P Fire and Rescue lights, as well as the Streamlight Poly-Tac series lights.

The inner diameter of the BlackJack Flashlight Holder ACE opening is 1 1/8".