Iris Diaphragm  (1920s and earlier?)
Strand

Iris Diaphragm (1936)

Aluminium casting with brass leaves. Lever movement. 
5 inch aperture to blackout. 
 

Catalogue & Journal Entries for Iris Diaphragm in the Backstage Heritage Collection

Stage Lightning Lantern & Iris Diaphragm (1925)

Spotlight Accessories (1936)

Spotlight Accessories (1945)

Spotlight Accessories (1953)

Spotlight Accessories (1966)

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