You can find the SilencerCo ASR Flash Hider 5.56 1/2x28 here. Fast $9.95 shipping! Orders over $200 ship for free!

The SilencerCo ASR Flash Hider is a 3-prong flash hider designed to be compatible with the Specwar, Saker, Omega, Hybrid, and Harvester Big Bore ASR mounting systems. The 3-prong design effectively eliminates the tuning-fork effect that is common with this type of flash hider, as well as greatly reduces the flash.

Caliber: 5.56
Threads: 1/2x28