^ Yes, those. Beware cheap imitations, as the tolerances can be off and they don't clamp securely.
They're a simple design, but work well. A vast improvement on the more complicated (and more delicate) mounting system of the older eTrexes.
I back it up with a lanyard looped around the bars, because there's always the unforeseen. But so far, I've only had Garmins escape from their mounts in actual crashes.