found at Camera House
The technical details behind this filter holder
The Laowa Filter Holder is designed for the 12mm f/2.8 Zero- D lens. It allows you to mount 100mm square filters or 95mm round filters onto the front of the lens. Use a circular polariser to cut glare, or up to 2 square filters simultaneously, perfect for long exposures and landscape photos.
Key features
Rotates 360 Degrees
Aluminum Construction
For 12mm f/2.8 Holds 2x 100mm square filter