Rings are very complex as far as material and design, and to be honest, there are not that many 2-stroke ring manufacturers. In the 2-stroke world, I only now of one company that manufactures both pistons and rings for 2 stroke engines, could be more but not many. The vast majority of 2-stroke piston manufacturers source the rings from a few other company's and then it's the balance between cost, cylinder plating nikasil composition, sealing, and coatings/plating applied to the rings. There are basically 3 types of base ring material, cast iron, ductile cast iron, and steel, then a huge number of available treatments and coatings to those. Just so people know, when you said chrome moly rings, you were referring to a ring with a moly (molybdenum) coating applied which has fast sealing break-in but may not be as durable as some other coatings.