Manolo
It doesn't seem to have an air tank and so far I haven't needed one. It does however have an Air pressure gauge, Moisture filter and Pressure regulator included. So far I have used it on about 3 models:-
1/72 F-14 Tomcat (Tamiya Acrylics)
1/32 MGB (Humbrol Enamels)
1/32 F-14 Tomcat (Tamiya Acrylics)
Very easy to use just switch on, 5 seconds later pressure built up to Static pressure of about 50 PSI and away you go.
Im reading the side of the box it came in and it says " it is the ideal compressor for the new or casual user".
One more item about this is it is very quiet.