Theoretically Stenocactus multicostatus (these used to be in the genus Echinofossulocactus) is easily recognized by its multiplicity of thin, wavy ribs, frequently having twice as many as its nearest competitor. The latest taxonomy has at least three other widely known species names lumped in as synonyms under S. multicostatus, including S. erectocentrus, S. lloydii, and S. zacatecasensis. Personally, we would follow the path that gives us more species names just so we can have a bigger collection. However, if this is not S. multicostatus, we are not clear on which of the other three species names to attach to our plants. Therefore it stays as is, and you can purchase several in order to sample the variation.