I

Illustrations and extensive description of the items listed below can be seen in Dennis Laney's definitive Leica 1984 Accessory Guide courtesy of Mike Butkus

Leica Code	Description	Production Year	Remarks
IASUU	Stereo polarizing spectacles in a plastic frame	19??-19??	-
IBSOR	Single exposure shutter used with OLEYO and OLIGO housings Forum discussion	1939-19??	NY item
IDCOO	M3 leather ready case	1954-1968	-
IFLEX	Scientific version of Visoflex I with rotating clear or diffused focusing screen in screw and bayonet versions Fontenelle archive	1953-19??	-
IFSTA	Adjustable filter stand copy accessory	1939-19??	-
IGEMO	M3 body only	1954-1968	10150
ILNOO	Elmar (II) f= 9 cm 1:4 collapsible	19??-19??	-
ILNOO-M	90mm f/4 Elmar collapsible M-mount	1954-1968	-
ILLUM	Copy stand 2 pair lamp attachment for 2" diameter column	19??-19??	NY item
ILNUU	Stereo projection attachment for twin 85 mm Hektor lenses used with PRADO projectors	19??-19??	-
IMARO	M3 (IGEMO) with F = 5 cm 1:3.5 Elmar	1954-1968	-
IMFIN	Universal viewfinder knon as "Imarect"	ca.1942-19xx	NY item
IMOOP	MP and MP2 body	1956-1959	-
IMPUU	Stereo projection attachment for twin 50 mm Elmar lenses used with PRADO projectors	ca.1956	see Westlicht 22/249
IMPUU -IZOUU	Stereo projection attachment for twin 50 mm Elmar lenses used with PRADO 250 and 500 projectors	19??-19??	-
INVOO	Forum discussion	19??-19??	00001
IROOA	Hood for 35 & 50 mm lenses with E39 mount; black with wide chrome band; earliest engraved "Summicron-" without code word; later versions had "IROOA"; last with catalog number JCB's a little...IIIg - JCB's a little...M3	1959-19??	12571
IROOW	Cap for 28mm f/2.8 Elmarit I and 21mm f3.4 Super-Angulon [1]	1964-1976	14042
IRZOO	M-mount adapter for using 35 & 50 mm Leica screw-thread on M-cameras Forum discussion [2]	1956-19??	14097 see
IRZUU	Stereo projection attachment for twin 100 mm Hektor lenses used with PRADO projectors	19??-19??	-
ISAIO	M3 with F = 5 cm 1:1.5 Summarit	1954-1968	-
ISBOO	M-mount adapter for using 90 mm Leica screw-thread on M-cameras Forum discussion [3]	1956-19??	14098 see
ISBUU	Stereo projection attachment for twin 120 mm Hektor lenses used with PRADO projectors	19??-19??	-
ISOOZ	M-mount adapter for using 135 mm Leica screw-thread on M-cameras Forum discussion	1956-19??	14099 see
ISUMO	M3 (IGEMO) with F = 5 cm 1:2 Summicron II	1954-1968	-
ISUMO-N	M3 (IGEMO) with F = 5 cm 1:2 Summicron II-DR near focusing range	1954-1968	-
ISUMO-S	M3 (IGEMO) with F = 5 cm 1:2 Summicron II-Rigid	1954-1968	-
ITDOO	Hood for 3.5 cm Summaron and 5 cm Summicron with narrow chrome band and velvet lining for reverse positioning	1956-1960	Forum discussion
ITOOY	Hood for 3 cm Elmar with E39 front flange; early version engraved "Elmar-"; late version with wide chrome band JCB's a little...Ig	1956-19??	12580
IUFOO	Hood for 9 cm Elmar and 135 Hektor; black with narrow chrome band at lens; wider chrome band; all black last version	1956-19??	12575
IVZOO	Cap that screws into M-mount body	19??-19??	14056
IWKOO	Hood for Super-Angulon f= 2.1 cm 1:4 with double trigger fastening Forum discussion	1960-19??	12502
IXMOO	Reloadable metal cassette with chrome tab; new version	1966-19??	14006
IZQOO	Rear dust cover for M-thread lens	19??-19??	14051