Welcome to the forum. As others have said it is a model 66. It was and still is a very popular model in 357 Magnum. Many cops carried one on or off-duty when their agencies allowed them. When I was a Private Investigator I carried a 2 1/2" 66-2 which my wife now has for her gun. You have a keeper there. There are few revolvers by any manufacturer that is as popular as the 66. Rust resistant (not rust proof), 6 shots, 357 Magnum/38 Special, medium size; not much more to ask for in a true working gun. Enjoy it, take care of it and should you ever need it for defensive purposes it will take care of you.