The difference lies in the construction of the softbox. If you often transport and set up the box, the Light Dome II is more convenient because the struts can be easily folded out and back in again. With the Light Dome SE, the struts have to be plugged in, which is more tedious. Of course, this also comes at a price. So if the box is in a studio and doesn't always need to be folded up, then the SE should fit the bill.

The mechanism for setting up and dismantling was revolutionary in the beginning. Now others have copied the system. It is worth looking on the internet because the price is considerable.