Actually RSMMC and RSMMC Mobile are the same, just that RSMMC Mobile has Dual Voltage(1.8v, 3.3v). The Meaning of Dual Voltage is that it can be use on all phone that are using Single(3.3v) or Dual Voltage(1.8v, 3.3v) MMC slot. Most of the new phone support RSMMC Mobile couse it support lower voltage(1.8v instead of 3.3v) mode to reduce phone battery demand. RSMMC Mobile can also be use on a Single Voltage MMC slot just that it will use maximum voltage(3.3v).

Trought my experience I have tested using RSMMC and RSMMC Mobile on both Ngage and QD. The result shows that both can support RSMMC and RSMMC Mobile but it only can support up to 512MB only, above than 512MB the phone will not support either it will "Hang" or it will not "switch on" at all.

For my advice, is better to test the card on the phone before selling it couse not all phone(same model) can use the same brand(kingston, kingmax etc.)of cards, some phone card slot are choosy it only support spacific brand.