There is general confusion regarding the part number for these filters.There were four types of CRT filters for 2400's.
378-0199-00 replaced by 378-0199-03
378-0199-01 replaced by 378-0199-04
378-0199-02 replaced by 378-0199-05
The initial three (-00 thru -02) were made of polycarbonate and the replacements were made
of acrylyc which made them more scratch resistant and they could be cleaned using
pure alcohol. They were all blue but only the first ones (-00/-03) are for standard instruments
while the others (-01/-04 & -02/-05) are for OPT 05 (TV Trigger) instruments. I don't know for
sure but a qualified guess is that they have a Video graticule possibly NTSC and PAL.
378-0208-00, clear made of polycarbonate, no replacement
Hope this cleared some of the confusion.