Beseler heat absorbing glass question

[xkaes]

I've got a Beseler 45MXII with the standard condenser head. This question might pertain to other Beseler 45 enlargers, but it may not.

Does anyone have the Beseler heat absorbing glass? It is inserted above the condenser assembly and has a CAT# of 8077. The exploded view shows a spacer ring (6) that fits between the top of the condenser assembly (7) and the heat absorbing glass (5). The spacer ring has a PART # of 555-20-16. Since the spacer ring has a PART # instead of a CAT #, I assume that it comes with the enlarger, but mine lacks that.



My question is, what is the diameter and thickness of the heat absorbing glass? Any information on the spacer would be great as well.