From Manufacturer
The clamp-on Wooden Camera Zip Box Pro 4 x 5.65" Clamp-On Complete Matte Box Kit includes the 114, 110, 104, 100, 95, 87, 80mm interchangeable clamp-on backs. This allows you to mount the Zip Pro on a variety of lenses by simply changing out the clamp-on back. Fitting neatly between the UMB-1 line and the original rubber Zip Box, the Zip Pro is a lightweight yet durable matte box with interchangeable mounting systems. The Zip Box Pro accepts up to three 4 x 5.65" (Panavision-style) filters without the use of filter trays. If reflections from light sources in frame are a concern, they you can tilt up to two filters in the matte box to help move the reflections out of picture area.
The clamp-on backs are interchangeable, allowing you to work with lenses of different diameters, or you can convert the Zip Box Pro to a swing-away matte box (swing-away bracket not included). It is recommended that you use a lens with a non-rotating front when working with a clamp-on matte box. An included carbon fiber top flag helps block veiling glare or bright reflections from striking your lens, and can be folded down to cover the front of the matte box and provide protection to the front of your lens.