This is a HKS model 10-A speedloader for 6 shot .38 special or .357 magnum revolvers.
Fits Models:
Dan Wesson- 65, 66, 80, 82, 606
Charter Arms- 65, 66, 80, 82, 606
Rossi- 851, 951, 971
Smith & Wesson- 10, 12, 13, 14, 15, 19, 64, 65, 66, 67
Taurus- 65, 66, 80, 82, 606