A Photon Flash Grenade is an Imperial grenade often used by the troops of the Astra Militarum that detonates like a small star, blinding anyone nearby and producing a flash bright enough to overload most visual protection systems like visors. Those caught without eye protection are usually left temporarily blinded and defenceless. It is used to carry out infantry assaults on enclosed structures and is intended to shock and disorient its targets.
- Rogue Trader Core Rulebook (RPG), pg. 127