This kitten below is our Tinkerbell aka Tinky. She is teacup or toy kitten. In age 2 month her weight is only 0.8 lbs (compare to her litter mates 1.7 lbs)

What is a Persian teacup cat?
Teacup Persian cats are miniature cats, and so they do not grow to the size of most other breeds of cats. Females are usually about 3-6lbs and males 4-7lbs.
Teacup cats have become incredibly popular over the past few years in particular and with many families living in apartments and small houses, pet owners have come to find that these smaller cats fit perfectly in their downsized living quarters.
But...
THERE IS NO SUCH THING AS A TOY OR TEACUP PERSIAN BREED !
Teacup cat is a Pet Quality cat and currently none are recognised as breed by major registries. Breeders who are trying to improve the breed - are working to breed away from this small size, as a standard size Persian should be a medium to large cat. However some breeders present these cats as their ?new? breed line and charging enormous amounts of money for their kittens.
Anyway, they are super cute.

Sometimes peaple ask me what is tortie kitten? What is Tuxedo? Why the kittens so different from mother color?

Actually its a lot of information about cat colors. And what I wrote here just a repeated from other publications. Anyway, if you are already here so you can get also a bit of information.

Cats, both pedigreed and domestic, come in a rainbow of colors and patterns. These are all a matter of genetics, so a calico mother might give birth in one litter to calico, tabby, and solid or bi-colored kittens, depending on her genetic background and the background of the male cat(s) that fathered the litter.

Cats, come in three basic colors (called "self" by geneticists): red (commonly called "orange," or sometimes affectionately referred to as "ginger," or "marmelade"), black, and white.

Common Color Patterns in Cats:

•Solids

•Tabbies

•Tri-color

•Bi-color

•Tuxedo

•Points or Pointed Markings

Tri-color cats include:

•Calico

Separate solid blocks of color, which must include red (orange), black, and white. They also may have blocks of tabby pattern, which produces an extremely colorful and beautiful cat. Dilute calicos, have the same separate blocks of color, only the colors are "diluted," i.e. "faded" shades of the original, which gives them an ethereal appearance. A dilute calico will have pale orange or buff for the red, and gray (or "blue") for the black.

•Tortoiseshell AKA "Tortie"

Torties are not true tri-color cats, because they do not all contain white. Instead of solid blocks, torties' coats weave the black and red throughout, creating a tapestry of color.Tortoiseshell cats may also be dilute, with softer versions of the colors. Like the tabby, some torties may also have white accent markings, creating a "tortie with white."

•Tuxedo

Tuxedo cats were so named for their glossy black coats, enhanced with white bibs and "spats," (less flamboyantly described as white feet).

more information here
more about color patterns and genetics here