Super Single Six. Interchangeable .22 long rifle and .22 magnum cylinders supplied. 9 & 1/2 inch barrel. AS10264 is probably a product code.
I had a single six convertible, 6.5 inch barrel in stainless steel. I still regret sellign it some 5 years later. Never miss fired, more accurate than my ability to shoot it, light and well balanced with a crisp single action trigger.
I highly recommend the single six, but unless you intend to do a lot of long range shooting the 9.5 inch barrel is too long.