@delpha

To markup different product sizes with schema.org, you can use the Product schema type and include the offers property within it. The offers property is used to describe the offers for a product, including the availability, price, and condition.

For each size, you can create a separate Offer item and specify the itemOffered property with a Product item that represents the product with that specific size. For example:

<script type="application/ld+json">
{
  "@context": "http://schema.org/",
  "@type": "Product",
  "name": "Example Product",
  "offers": [
    {
      "@type": "Offer",
      "itemOffered": {
        "@type": "Product",
        "name": "Example Product - Small",
        "size": "Small"
      },
      "availability": "http://schema.org/InStock",
      "price": "10.99",
      "priceCurrency": "USD"
    },
    {
      "@type": "Offer",
      "itemOffered": {
        "@type": "Product",
        "name": "Example Product - Medium",
        "size": "Medium"
      },
      "availability": "http://schema.org/InStock",
      "price": "12.99",
      "priceCurrency": "USD"
    },
    {
      "@type": "Offer",
      "itemOffered": {
        "@type": "Product",
        "name": "Example Product - Large",
        "size": "Large"
      },
      "availability": "http://schema.org/InStock",
      "price": "14.99",
      "priceCurrency": "USD"
    }
  ]
}
</script>

In this example, the main Product item represents the product as a whole, and each Offer item represents a specific size of the product with its own availability, price, and size information.

#size