This is a really nice grafted mammillaria measuring around 6 to 7 incheas long is sold grafted onto stem of Hylocereus.
It needs a well-draining potting mix. Water thoroughly and let the soil dry at least halfway down the pot before watering again. In winter, decrease or withhold water.
Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz
