On the backside of every Tommy Armour 855s iron, there is a little circle with an X in it. It is located near the center, at the top of the cavity cut-out, right above the "855s" marking. On some sets, the ring around the circle and the top and bottom parts of the X are painted in black, while on other sets, the paint is yellow. I'd like to know what the black and yellow paint indicates about the different sets? I don't think it is lie angle, as there are marks on the hosel for that, but I could be wrong. Nor do I think it is shaft type or flex . . .

By the way, you don't see the same "circle with an X in it" mark on any of the 845s Tommy Armours, so far as I know. On the 845s models, that area is blank.

Can anybody help?

Thanks,
/s/ Rush