This was a grenade added to commemorate Veteran's Day 2010 and AVA's 1st Anniversary. It seems to have a longer fuse than other grenades, and it explodes in a brilliant flash of multi-colored sparks. The explosion, both sound and flash, appear to be based off a firework.
Its damage is on par with the standard grenade, with no special damage boost or vision obscurer. It was distributed during the holiday, and it later expired a week later.