The G.D.O. (aka Garage Door Opener) is a Tau'ri device that transmits a signal to the S.G.C. computer, identifying the SG unit so that the SGC can open the iris covering the Earth Stargate.

A G.D.O. and iris code (a sequence of numbers that must be manually entered into the G.D.O.) is assigned to every member of every SG team. The codes can be altered if one of the devices is compromised. If a team is captured or too long overdue, their G.D.O.s are locked out of the system, resulting in the team being left permanently stranded on the planet they're on and ultimately unable to return to Earth. (SG1: "Children of the Gods")
-SGCommand Wiki

Exported from The Carter's Addon pack for garry's mod. like the Wraith Dart i posted.
I did not make this model, only modified it a little for prop usage.

To my followers, i like Stargate, especially Star Gate Atlantis so i might export a few more models. might make some from scratch later on to.

First pic is my print of the thing, ignore my thin xenomorph arms.
Second pic is from the show SG1 was good reference for painting.