After the team beams the mine onto the ship, Carter walks into the shot. As she does you can see an outline of the composited rings device on her leg.
When they beam the mine off the ship it remains cloaked, even though a few minutes later they state they cannot rescue Teal'c while cloaked.
When Jacob/Selmak takes over the stick from O'Neill to try to save Teal'c, the boom mic is clearly visible.