Google ADs Dynamic Remarketing - purchase

<script>
gtag('event','purchase', {
  'value': 998.55,   // The monetary value of the event. * Set value to the sum of (price * quantity) for all items in items. Don't include shipping or tax.
  'items': [
    {
      'id': 1234,                           // A unique product identifier. The parameter value must match one of the following attributes from your Google Merchant Center Product Feed: id, item_group_id, or display_ads_id.
      'google_business_vertical': 'retail' // Specifies the type of feed used to lookup the product. Value must be set to "retail".
    },
      {
      'id': 2345,                           // A unique product identifier. The parameter value must match one of the following attributes from your Google Merchant Center Product Feed: id, item_group_id, or display_ads_id.
      'google_business_vertical': 'retail' // Specifies the type of feed used to lookup the product. Value must be set to "retail".
    },
  ]
});
</script>