The autocomplete widget you are using is ffor setting references. For instance, if you have one entity with Person and another entity with CountryOfResidence, you could use the autocomplete widget in a page showing a Person to enable the user to type in part of the country name to select the CountryOfResidence for that person.
It seems like you are trying to use the widget to set the value of an attribute on the Products entity. This should simply be typed in by the user.