You can see an example here:
<script type="application/ld+json">
{
"@context": "http://schema.org/",
"@type": "Product",
"name": "Executive Anvil",
"image": [
"https://example.com/photos/1x1/photo.jpg",
"https://example.com/photos/4x3/photo.jpg",
"https://example.com/photos/16x9/photo.jpg"
],
"description": "Sleeker than ACME's Classic Anvil, the Executive Anvil is perfect for the business traveler looking for something to drop from a height.",
"mpn": "925872",
"brand": {
"@type": "Thing",
"name": "ACME"
},
"aggregateRating": {
"@type": "AggregateRating",
"ratingValue": "4.4",
"reviewCount": "89"
},
"offers": {
"@type": "Offer",
"priceCurrency": "USD",
"price": "119.99",
"priceValidUntil": "2020-11-05",
"itemCondition": "http://schema.org/UsedCondition",
"availability": "http://schema.org/InStock",
"seller": {
"@type": "Organization",
"name": "Executive Objects"
}
}
}
</script>
This come from https://developers.google.com/search/docs/data-types/product -> Examples -> Single Product Page -> JSON-LD Example -> SEE MARKUP.
The field value for example is: https://schema.org/NewCondition
Thanks a lot