I make them and have installed 20 plus sets and sold maybe another 20 through the years without complaints. I have replaced at least 3 sets from other venders--sorry for the self serving toot--just passing on the info.
They are one piece compound shaped (curves in both direction), not a formed version (curved on only one direction) which has no shaping at all and will not fit an early car. The factory rocker built for later cars are formed only and will not fit an old car.
Here is a shot of one just installed on a restoration. They are stressed in a way that requires clamping them in multiple locations during the install making the rocker assembly (outer, center, inner) much stronger and they also have original looking drain divots in the bottom.
Kirk
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