I liked the spring clamp, but tweaked it to add some features of some nice clips I've picked up as promotional swag over the years. Namely, I rounded the ends and added teeth.

I also scaled it up, to something resembling what I thought I was seeing in the pictures.

This is actually based on this variation: https://www.youmagine.com/designs/simple-spring-clamp/.

I recommend ABS or HIPS for the spring. PLA has a tendency to just snap.

The spring should probably be a bit shorter.