That's the three spirals design.

It does have differing executions though. A particularly nice one is like the one in that link, with the extra wiggles at the top, and some of the trails being quite thin as well as thick, as opposed to without wiggles and no variation in thickness.
Here's a couple of images (one with light reflecting off the surface, the other with light coming through) of a similar charger, but a different execution. No wiggles and thick, even trails.
Also, images of two bullet bowls, one much larger and more finely blown than the other, but with the much more elegant wiggles and varying widths of trail.