I bought a speed control, I think from Grace (have to ck the box), and had to specify the machine for it to be compatible. It plugs into the port that is used by the foot control and has a dial for speed setting , as well as a start/stop button. It does not require your machine to be on a frame, but comes with Velcro strap that attaches the control directly to your machine. I never got adept at the stopping & starting button and only used it a short time before getting a frame, machine w/stitch regulator. The stitch regulator works with rails…I LOVE it. My speed control languishes in a drawer!