A Pair of Exotic Shells same family one brown / cream and the other white / blue

I have looked every where for the scientific name or common name for this shell and can't find it if you know can you please let me know… They are quite unique due to their flat back at the end most shells spiral at the end…. These are a pair of beautiful shells both from the same family both different in colour. Dimensions: 7cm Long, Diameter at the end is 4.2cm We combine shipping take a look in our Homewares Department in our store, under POLISHED SHELLS, for our whole collection. Customer

NOTE: As all shells are organic, not one shell is the same, slight colour/pigment variations may occure to the one pictured. Also there may be upto a 3% size variation + or - as described. If you are an overseas buyer, please check with your customs and quarenteen departments, we will not be held liable for seazed shells or costs of treatment for important organic materials.