From the Loftsmith community

Twist-zoom lens barrel

A lens barrel you can twist to zoom, for camera or optics projects on the bench. The black ring has ridges all the way round, so it turns easily in your fingers, and a little arrow on the orange collar shows where you are. You can change how far it travels and how much of a twist it takes.

6 parts · 93 g · 74 × 74 × 60 mm