The product and customer inputs let the user pick a set of existing products and customers from the master data. The two inputs work in the same way, just use different tables for data selection.
The value of this input is CustomerGroup or ProductGroup object. It is often transported as a Map when value is passed between logics over HTTP, so you may need to convert the input map to the object first.
Product
The product filter allows the user to provide a set of products as an input. The end user can either select products from a list, or provide a filter that will be used to query the product master table.
Customer
The customer filter allows the user to provide a set of customers as an input. The end user can either select customers from a list, or provide a filter that will be used to query the customer master table.