The next step from an I'D
This is a sort of "no frills" version of the Petzl I'D. The I'D is a great ascender/descender for beginners, as there are multiple additional safety features built in, including a spiked cam that holds the rope if the device is turned or threaded wrong, and a panic re-set if the handle is pulled too far. These safety features come at the expense of a large, heavier unit, and the Rig is a smaller, lighter, and more compact version that does not include these additional features. After several years with the I'D, I moved to the Rig. I like the small size, ease of threading without detaching from my harness, and ability to use as an ascender and descender.