In case you are participating in the OSS procedure taxes must be calculated based on your customers countries’ tax rate (for a B2C inner EU shipment).
Some products (e.g. coffee) have different tax classes (e.g. standard, reduced, greater reduced, super reduced) in different countries. For that use-case the plugins adds a convenient way to choose country-specific tax classes for specific products.
Edit your product and choose the Add country specific tax class button to add a new tax class for a specific country. Choose the country and the tax class and save the product settings.