The killFLASH ARD in Flip Cap Optic Cover from Vortex is designed to reduce the muzzle-side reflective signature from a riflescope's objective lens.
The flip-up cap provides protection for the optic during transport and storage. The integral ARD honeycomb insert also serves as a sunshade and a lens protection device.
This is the size 6 cap - it fits the following Vortex riflescopes; Viper PST 2.5-10x44 - Viper 3-9x40, 4-12x40, 6.5-20x44 - Diamondback 3-9x40, 4-12x40, 4-12x40 AO - Crossfire 3.5-10x44, 4-12x40 AO
Fits objectives with an outside diameter that measures approximately 1.84-2.2"