From Stargate Wiki
12.9 metric tons
Ring Transporters are a type of teleportation technology used by the Ancients, Goa'uld, Tok'ra, Jaffa, Lucian Alliance, and Tau'ri. These transporters work in pairs: the matter inside them is swapped with the other one. They operate raising or lowering a set of rings to circle the transportable object. No weapon has ever been shown to penetrate this circle.