These have a pretty strong magnet attaching them in the center. Doesn't take up very much space and the metal isn't flimsy.
I like how convenient the attachment system makes them when trying to use them. The typical "ring" attachment becomes very much in the way when trying to cook. The magnetic connection makes it easy to separate the size needed and I can even keep together specific ones for any task, making it less likely that I'll have to spend time searching the counters for a single, unattached measuring spoon like I usually do.