Hi Garibeos
my partner, MHD, also has a Mares Azimuth and it too does not have a serial number. MHD has previously had difficulty getting info from the manufacturer as he was unable to give them a serial number.
Maybe the unit was new to the guy you bought it from, but had been sitting around in shop storage since its manufacture. or maybe he bought it and never dived it.
As we are in Australia and the scrubber weighs a ton, it will be interesting to see what arrangement the manufacturer will come up with. sending to italy won't come cheaply or quickly. preferably just send out a new one if we provide evidence that the old one is destroyed. in the mean time, as i'm not diving, MHD can use my SK.
rachel