The secret is on the inside.

Rich latigo leather on top with iridescent lining that catches the light like the inside of a shell - shifting between teal, green, and deep violet depending on how the light hits it. 

Built the same way every Sexy Beast collar is built: by hand, in Philadelphia, with hardware that won't quit and leather that only gets better with time. The iridescent finish isn't a coating. It's the leather itself.