
Window projectiles are designed to be fired from naval vessels to disrupt enemy radar operations. The projectile may be used to provide a false screen behind which our ships may maneuver or approach undetected, or to provide a false target for enemy radar. The projectile itself consists of an illuminating projectile body fitted with a nose time fuze and an expelling charge of black powder. Ignition of the expelling charge by the fuze discharges a payload of foil strips which form a reflecting cloud for radar beams.
No information about functioning.
OP 1664, Volume 1 - US Explosive Ordnance (1947)