Platter size and cache

I think buy WD5002AALX. But i am not found information about platter size of these products. If new (WD5002AALX) one has a single platter, i will buy it. Old one is two platter , i know but why i didnt found any information about this specifications .
And some page ( say it (WD5002AALX)has 64mb cache another page ( has 32 mb cache

Hello there,

I have received information from WD that the WD5002AALX model is a single platter design.

Source: Phone support.

Thank you.