The Pro 4 Hood was a unique design that allowed four effects filters to be loaded up and quickly flipped over the lens before taking a shot.
Each of the four flaps has a clip frame to hold a Cokin A series or other 67mm square filter.
Benefit as well as speed is once the filters are in place you don’t have to handle them so they don’t get marked as easy.
The hood was popular with medium format wedding and portrait photographers, but can also be used on 35mm and digital cameras.
You can buy one here: Pro4 Hood along with various size adaptors.
Here’s a video of how the Pro 4 Hood works.