The 617 was a 2015 Special Edition and has the super domed sapphire. It's like a black 127 "Fiddy", as is the 375, but the 375 has more of a tobacco dial. The crown guard lever is going in the normal upward position, it's limited to 300 pieces, whereas the Fiddy is 1000. It's DLC coated titanium and I love the OP logo on the dial instead of 1950. It's a sleeper that the masses (followers) have overlooked.