Mammillaria Longimamma

Mammillaria longimamma, commonly known as the Finger Cactus, Nipple Cactus, or Pineapple Cactus, is a distinct species of cactus native to the dry shrublands of central Mexico. It is easily recognized by its exceptionally long, finger-like tubercles (the "nipples" that give the genus its name) and its large, vibrant yellow flowers that bloom in summer. 

Pot size 2.5" 
first  picture is for reference only,
You will receive a similar size plant shown in other pictures.

"Sizes are approximate" every plant is slightly different then others and due to your screen setting and different screen type.

Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz