I think one of my favorite things about this is that it actually makes product information available in the meta tags.

<meta property="twitter:item:variant1:id" value="n6NDAWFNqjkNZftJWq0BQw==" /> <meta property="twitter:item:variant1:title" value="Small" /> <meta property="twitter:item:variant1:inventory_count" value=1 /> <meta property="twitter:item:variant1:price" value=75000000 /> <meta property="twitter:item:variant1:tax_category" value="included_in_price" /> <meta property="twitter:item:variant1:last_updated" value=1409259500000 /> <meta property="twitter:item:variant1:attribute1:text" value="Small" />