you can find a product’s item number directly on its product page, on the right-hand side under the section “Material & Care.”
At the very bottom, the item number for that specific product is always listed.
Please use Giesswein page for your country:
Giesswein DE / EU Homepage (German)
Giesswein EU-Europe (Englisch)
This way, you always have all the important product information – including the item number – right at your fingertips.