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Message: <blockquote data-quote="Jim M." data-source="post: 1317771" data-attributes="member: 60675">Not really, because the first sentence is unclear.  I think part of the problem is that you used "and" when you meant "or".  (I say this as someone who used to teach logic).  I guess what you meant to say is that "prominar" applies to any scope that uses either ultralow dispersion OR extra low dispersion glass.  And then you say "now called XD or ED".  It is also unclear what that last phrase modifies -- both ultralow dispersion and extra low dispersion, or just extra low dispersion?To make things even more confusing, I linked to information on the Kowa-USA website, while you linked to information on a different Kowa website.  And these two actually use different terminology.  If you look at the website I linked to, it actually includes the word "fluorite" in the description of the 663, while the website you linked to limits it to the 883.  Moreover, the website I linked to says both the 773 and 883 use XD glass-- but I guess you are saying the 883 does not -- it uses ultralow dispersion glass?.Not sure if anyone else cares at this point, but I remain somewhat confused.Cordially,Jim</blockquote>