update product custom attribute API JSON format

I was using the postman to send post request.
I have a single json payload send to API endpoint, which is success

rest/default/V1/products/

{
  "product": {
    "sku": "203-197-1022",
    "custom_attributes": [
      {
        "attribute_code": "description2",
        "value": "CHECK CHECK 555"
      }
    ]
  }
}

But if I try to add multiple items in the payload, it doesn’t work. It just only update the last SKU. Can anyone help to check what’s wrong with my json?

    {
  "product": {
    "sku": "203-197-1022",
    "custom_attributes": [
      {
        "attribute_code": "description2",
        "value": "CHECK CHECK 555"
      }
    ]
  },
  "product": {
    "sku": "728-207-1022",
    "custom_attributes": [
      {
        "attribute_code": "description2",
        "value": "CHECK CHECK 555"
      }
    ]
  } 
}