FOR SALE: Is there a quick and easy way to tell a 610 from an 820 ?

[Mark Loraine]

Well that kinda makes sense to me cause the SA 606 came with thin rings, but the SA 822 looks like they are the standard wide cast iron rings.

I'm going to assume 606 is a 610 and the 822 is a 820?

If there happens to be a chart with the Special application models listed, I sure would like to have a pdf file of such.

Thank You Louie!