The ExpoDisc (4x5.65") waist level lens is clean and working

lens is clean and working well

but it’s worth noting

front and rear caps

Interior dimensions are approximately 10x16x25cm

You'll have some difficulty finding 2x3" sheet film

The ExpoDisc (4x5.65") waist level lens is clean and workingThis particular Expodisc is not a disc it's a big 4x5. 65" slab designed to slip into matteboxes but it works the same as the classic. Basically, it's a specialized flat diffuser designed to facilitate setting custom white balance. Rather than hauling around a gray card, or trying to find a plain white surface, or hoping that your camera guesses correctly, you can toss this in front of your lens and lock in an accurate custom white balance in seconds.