You can make SCMRs with a shuttle and ball, allowing single rings, trefoil rings, and other combinations on the ball thread. However, we suggest you work with two shuttles.

While constructing a chain and the desired position of a ring is reached, make a thread loop with the core thread.
The first double stitch should be brought up as close as possible to the previous double stitch.
After tatting the desired number of stitches as a chain, building the SCMR, pass the shuttle through the thread loop.
Hold the stitches in the pinch, pull the core thread to close the SCMR.
When beginning the next element past the SCMR, make sure the first double stitch is pulled up as close as possible.