This will fetch only such attributes whose IDs match with the selected products. Here, the ProductId is a custom formula field which fetches the Product Id of the Line Item object.
Lookup Display Columns
Select the fields to be displayed on the lookup dialog box.
Lookup Record Limit
Click the icon, enter the maximum number of records to query for the lookup field dropdown, and click Save. Default value is 200 to a maximum of 1000.
Junction Object Name
Click the icon, enter the name of the junction object which you would like to filter the lookup values, and click Save. This is a custom object that you can define to filter the values which do not exist on the Lookup Object itself.
Junction Field Name
Click the icon, enter the name of a field on the junction object which you would like to filter the lookup field by, and click Save.
Junction Default Flag
Click the icon, enter the name of a field API from the Junction object to determine the default value of a lookup field, and click Save. This field must be a checkbox.
Filter Criteria 2
This field is not available in the CPQ Admin UI. You must use Setup > Build > Develop > Custom Settings > Lookup Field Settings to configure it.