I have purchased a King size fitted mattress protector in the past when we purchased a mattress.  It was required for the warranty.  I fell in love!  I have more beds and so I ordered another one.  So easy to take off and wash every time I wash the sheets.  It is terry cloth on one side and vinyl on the other.  Nothing wet can get through.  You can not feel the vinyl.  Very soft.  Will buy another one when i buy another bed.