Customizable labels in custom fields For a new website I have a list of products with specs, but most of the time the specs are different for each product, because there are a lot of types of products.

Right now I just have a new field for every type of spec, but I want the client to be able to do this themselves.
Is there a module that enables me to customize the label for each field?

So let's say the client can add a field, fill in the label and value himself?
You can use 'Field collection' in your content type for products, In your  field collection field keep one field as label and other for the value. This approach will suit your needs