This is a flash diffuser for a Canon Speedlite 580EXII It may fit other Flash units the dimensions for the head are 76mm x 49mm. It works great when using it as a bounce flash and the diffuser adds a fill flash, you get two flashes in one.

You can print in low with 10% fill needs supports no raft and add 4 helper tabs placed equally spaced out on the ring.
I changed my filament at 80 mm to get the black base. You will see it start to print the tabs in the supports that is about 80 mm.

Must use clear filament to work as a diffuser!