In sixth season episode One Little Ship, these oversized isolinear chips were used in forced perspective shots in which the miniaturized O'Brien and Bashir surreptititiously try to rewire the still normal-size Defiant's warp drive encryption subprocessors, after the ship is captured by Jem'Hadar soldiers.
Solid acrylic with screen printed circuit patterns on both sides. Shown here with a normal size screen-used TNG chip.
From Propworx and the collection of Doug Drexler.
