From Leica Wiki (English)
- Production era - 1959-19??
- Code number - 16471
- Type - Visoflex extension tube for near focusing for Visoflex II/ III for use with with universal focusing mount OTZFO and lens heads
- Dennis Laney's Leica Accessory Guide (1st edition) page 49 courtesy of Mike Butkus
- Center image courtesy of Jan Dvorak
- Forum discussion