First off its the amperage that will determine if you are in danger or not. It will only take half a amp to give you a heart attack.
Voltage and wattage does not really matter very much. It only determines the level of discomfort.
Basically the difference between ouch and HOLY $*&t!
If you dont know what it is leave it alone.
If you are hell bent on masterbation sell the power supply and spend the money at a adult store.