• Front side - M77x0.75 female thread
• Rear side - 57mm inner diameter
• Outer diameter - 80mm

This adapter has two functions:

1. Allows using M77x0.75 filters on lenses with 57 mm outer diameter.
2. Allows coupling such lens with a matte box with 80mm opening.

Known compatible lenses are:

1. ISCO Wide-Screen 2000 MC.

Made of anodized aluminium. Front 80mm plastic snap-on cap is included.

Flat spring installed to protect a lens barrel from damage by set screws.