I know that they fit Solatube Models: 400850, 40051 - as I installed them into these models myself. The clips may fit other models as well. If you're not sure if they fit yours, buy them, and if they don't fit, return them.
My parents needed these for their Solatube DayLight Solar lights that they have in their house in Florida. They do not sell these anywhere on the internet so I spent the time creating them in CAD and I 3D print them to order.
The old plastic clips hold the light up in the ceiling, and as they age, the plastic gets very brittle and breaks when you take them down to clean out the bugs/dust and whatnot. These new clips work very well as a replacement.
The first photo shows the original semi-translucent clip and my version 6 white clip.