There are head lock devices made for this application, but I wanted something a little smaller and use items I had in my shop. The glo plug in my O.S. .90 four stroke is in a bad location (glad O.S. changed that ). Having an onboard glo driver in this plane I needed a permanent connection to the glo plug. What I used was a small wheel collar, a Sta Kon ring lug, (a number 10 or 14 is about the right size and matches the diameter of the wheel collar), soldered to the wheel collar, and a small piece of .030 lexan plastic with a hole drilled in it for the insulator.