The ExpoDisc (4x5.65") lens mount_Praktica Electronic Two camera platforms and one

Two camera platforms and one stopper block are included (both sides have an end stop

with some cosmetic wear from normal use and handling

but a solid user

The Linhof leveling head is essentially a very low-profile ball head with a 15-degree range of motion

The ExpoDisc (4x5.65") lens mount_Praktica Electronic Two camera platforms and oneThis 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.