Lakeside53
Stihl Wrenching
The only 2 Stihl products I ever seen with 1 ring was a 015 and a FS36 (line trimmer)
I think the idea is one ring offers less friction which reduces heat. Two rings seal better. Old 3 ring seal best but alot of power lost to friction. Which is better, ?
The rings take the combustion heat from the piston to the cylinder wall...