Cargo ship power coil
Cylindrical unit that is a key component of a cargo ship's power systems. One such device was once owned by the trader Inago. It was traded to (or stolen by) Vala Mal Doran, and eventually found its way into a monastery of the Goa'uld Grannus, where it became an icon for veneration (called the "Ring of Shen-Marak"). There it was protected from overly curious visitors by a small shield. The "relic" drew so many faithful pilgrims that it soon became the only item keeping the sanctuary operating after the Goa'uld's death.
The device was returned to Inago, who would not reveal why a "worthless" power coil was so valuable to him.
The Ties That Bind - Vala and SG-1 trade Caius's modified cargo ship for the power coil, which they return to Inago in trade for Arlos's mother's necklace.