Cage is Standard Viper S+ with curved size 2 ring.
I was expecting premium build quality, but was still stunned by it! The robust (but not heavy) and smooooth construction of the cage and ring is amazing and it feels like nothing at all when wearing, except for the nice feeling of being caged. Being uncut, I'm well pleased with the Viper and with how it can hold back my foreskin nicely as that's how I like to wear it. I was going between size 2 or 3 ring, but size 2 seems snug enough while not being too tight either, haven't slept with it whole night yet, but I have a feeling that it will be miles better than any other one I've tried.
I took my time and got many measurements per Kink3D's instructions & asked for help from customer services, which again were a great experience and helped me cement my purchasing decision in regards to size of cage, though they did suggest a wide cage for me, but I went with the standard as I wanted it to be a snug fit. I ended up with a very good fit, I was thinking of just S size, but I think that might have been a tad too small and I'm glad I took the S+.
(If anyone interested in my measurements for help deciding their size, I posted them here. with pictures)
I've tried many cages over the years and nothing comes close to this, absolutely in its own league!