(M) means capacitance tolerance 20 percent, visible in the picture. So 390 out of 470 means normal value
Solid BIG guys. The actual capacity measured by my multimeter was in the range 430-460 uF (supposed to be 470 uF), but this is still OK for my use and perfect for the price&shipping. The shipping took more than a month, which is usual for such small things from China. Tested in use for a few days and without any problem :)) Wo I can only recomment the capacitors.