What does the letter of IPHONE serial number mean?

USA \ x0d \ MC 608 ll/a _ 16gb black \ x0d \ MC 6 10ll/a _ 332 GB black \ x0d \ MC 3 18ll/a _ 16gb black \ x0d \ MC 365438。 Canada \ x0d \ mc603c/a _16gbblack \ x0d \ mc605c/a _ 32gbbblack \ x0d \ Japan \ x0d \ mc603j/a-16gbblack \ x0d \ mc660. Mc603kh/a _16gbblack \ x0d \ mc605kh/a _ 32gbbblack \ x0d \ x0d \ Philippines \ x0d \ mc603pp/a _16gbblack \ x0d \ mc605pp/a. Mc603x/a _16gbblack \ x0d \ mc605x/a _ 32gbbblack \ x0d \ x0d \ Germany \ x0d \ mc603dn/a _16gbblack \ x0d \ mc605dn/a. Mc603b/a _16gbblack \ x0d \ mc605b/a _ 32gbbblack \ x0d \ x0d \ France \ x0d \ mc603fb/a _16gbblack \ x0d \ mc605fb/a. X0d\\x0d\ Chinese mainland \ x0d \ mc603ch/a _16gbblack \ x0d \ mc605ch/a _ 332gbbblack \ x0d \ x0d \ China \ x0d \ mc603zp/a _ 65438. X0d\\x0d\ Macau, China \ x0d \ mc603zp/a _16gbblack \ x0d \ mc605zp/a _ 32gbbblack \ x0d \ Taiwan Province Province, China \ x0d \ mc603ta/a _ 65438. X0d\\x0d\ Singapore \ x0d \ mc603za/a _16gbblack \ x0d \ mc605za/a _ 332gbbblack \ x0d \ Malaysia \ x0d \ mc603za/a _/kloc- X0d\\x0d\ New Zealand \ x0d \ mc603x/a _ 16GB black \ x0d \ mc605x/a _ 332gb black \ x0d \ uae \ x0d \ mc603ab/b _/kloc- X0d\ Russia \ x0d \ mc603rs/a _16gbblack \ x0d \ mc605rs/a _ 32gbbblack \ x0d \ Greece \ x0d \ mc603gr/a _16gbblack \ x0d. Italy \ x0d \ mc603ip/a _16gbblack \ x0d \ mc605ip/a _ 32gbbblack.