This is a Safariland Magazine Pouch known as the Clip On Reload Carrier, model CD-2.
The CD-2 metal clip-on Speedloader Holder is an epoxy coated strong steel clip lined with a vinyl pad insert to ensure loader stability. Clips firmly onto any belt up to 2" (50mm) in width and designed for small frame 5-shot or medium frame 6-shot revolvers.
Features:
Fits any belt up to 2 in width;Reloader carrier;Designed for small frame 5-shot or medium frame 6-shot revolvers