The 5 x 1000 is the share of the Income Tax for Physical Persons (IRPEF), which can be assigned to non-profit organisations and activities with social aims, when making a tax return.
Donating 5 x 1000 to the Tethys Research Institute does not cost anything. It is not an additional tax but an amount that the State reserves for non-profit organisations.
The allocation of 5 x 1000 is anonymous. The Tethys Research Institute will not have access to taxpayers’ personal data