Dougall,
These are different shell not from amazon, these are sent by the breeder & it was identified as "Mystery Snail shells". Escargot shells sold by Amazon are completely different then these.
Dougall,
I did not know till y'day, I had put this is another forum too where someone identified these as mystery snail shells & sent me the reference pic which matched. When I saw your answer I replied back stating is mystery snail shells. However I've got shells from amazon which I have soaked/washed it and have put it into my new tank y'day, along with a few mystery snail shells which I have got.