US Projectile, 3 inch Illumination, Mk 28 Mod 1
These projectiles are for illuminating targets by a parachute flare. The illuminating projectile is a thin case with a very small expelling charge just behind the fuze and an interior assembly of a star or candle with a parachute and a very lightly held base plug.
The overall projectile color is light blue with two white stars.
Nothing else to see.
Collaborative Ordnance Data Repository