My Protege compared to a normal 901 battery, performs much better in three ways.
1) the battery life is alot longer, I can go 8 hours or longer one battery
2) there is no cut off time on the battery since its a manual pushbutton switch where as most 901 batteries have a cut off time
3) the peak voltage is higher than the peak voltage of a regular 901 battery, giving in my opinion more vapor production than the standard battery.
Hope that helps!
