I might be wrong Alfonso, but it looks like a common magnimamma to me.

Alessandro

G'day Alfonso, I think it may be Mamm lloydii, check out the pics on mammillarias.net, here's the link...

Mamm lloydii

Cheers, CP

Thank you both. I noticed today some flower buds appearing. I am going to wait, so the flowers can help.
Alfonso

Looks more like M. lloydii. It appears to have strongly-edged tubercles and three or four relatively even spines. M. magnimamma tends to have one long spine and then usually a few smaller ones, and less edgy tubercles. The two species are closely related and have somewhat similar flowers. M. magnimamma flowers should be a little larger and can be completely pink, but may also be white with red stripe. M. lloydii appears more like some M. magnimamma than some M. magnimammas do :)

The flower buds are comming, and appears to be white or cream with brown stripes, I am going to wait until they are full open.
Alfonso

The flower buds slowly appearing, and looks green
Alfonso

The flower buds are comming very slow,
Do you think in M. lloydi or M. karwinskiana?
Here is the new picture
{{gwi:488040}}
Alfonso

Now that I can see it more closely, those bristles in the axils and the flowers are more like karwinskyana.

CP

From the spines and tubercles I would have said M. lloydii, but that much wool is unusual and I've never seen bristles like that on M. lloydii. M. lloydii flowers are very pale with just a slight reddish striping. I've never seen them this dark.

M. karwinskiana certainly has wool and bristles like that and can have flowers like that. It usually has more, stronger, and longer spines but is very variable and sometimes has spines like this. The flowers are usually even more red than this but can be a mix of reddish a yellowish like your buds seem to be. My vote at this point.