Getting product dimensions and weight per API

Hello,

i am trying to get the exact product data from my shopware 6 installtion via API.
I need width, length, height and the weight.

When I make an API call to this URL http://192.168.121.131/public/api/product/018cee72a891734c95009a583ab5aeb7
i get the product details but most of the are null.

                        "weight": null,
			"width": null,
			"height": null,
			"length": null,

I am sure I saved the dimension correct.

Can anyone help?