Buon Giorno Adriano
You can purchase a very good quality Maroger at Kremer-Pigments. Well, my italian is extremely poor, but I found the right sites for you:
http://kremer-pigmente.de/italienisch/ihome.htm Distribuzione Italia at Zecchi, Firenze.
http://kremer-pigmente.de/italienisch/ibindem09.htm
(Claude Yvel Medium)
Nr. 79098 is a "ready to use" gel. However I would prefer the Nr.79099. you will get the 2 components and can mix up fresh as Richard mentioned above.
This Maroger is more similar to
http://www.oldmastersmaroger.com/ very rapid so use it sparingly, after few hours will be dry on your palette... but hey, meraviglioso!
btw: they are not expensive: the tube will cost 12.00 euro/ 50 ml
the set will start at 14.00 euro for 2*20 ml, but my best choice is 2*100 ml for 35 euro. (plus tax)
ciao!