This is a computer sensor or download tool that Racetrack uses to scan the Cylon Basestar computer in Season 3, Episode 7 "A Measure of Salvation". It's two parts, each custom made by the production for the show. One part has two prongs made of plastic held together with aluminum brackets. There are red LEDs mounted in the end of each prong to light them up (although one is not functioning right now). The other piece looks like it's made out an old TV tuner (or something) with blue LEDs mounted all over it, and encased in a acrylic tube. Both run on 9-volt batteries.

Here's a picture of both items, the second shot is with the room lights off so you can better see the LEDs:

Here's a couple of screen shots showing Racetrack in the background pulling this out of a case: