Escobaria snedii . Absolutly winter resustant in UK and all norten Europe. Sutable for greenhouse or dry rock garden. One of my faver kind of  cacti. Semi-adult - , about 3.5 - 4 cm. . some blooming  this year. Will be send bare roots, no pot or substrate. Dispatched with Parcel2Go, tracked........

Photo 1 and 2 show mother plants in flouers.

Photo 3 and 4 plants size you can buy....