https://www.belkin.com/hk/en/product-registration/?pid=AUD008fqSA&directRegistration=true
Noise Cancelling Over-Ear Headphones
Noise Cancelling Over-Ear Headphones
SKU: AUD008fqSA

2. Purchase details

Optional serial numbers are alphanumeric and contain 11-14 characters.
This number will only be used to validate your account when you call support