Sorry folks, I didn't make our question clear and created the confusion. I do have regular charger for my ultrastinger and fast charger for regular stingers. This is exactly my problem. I have 5 chargers on my desk - chargers for 9AN, 10X, UltraStinger, regular Stinger and consumer-sized Nicad/NiMh such as AA, AAA, D... Etc.
If the new fast charger for US is compatible with regular stingers, it could replace 2 of my current chargers off my desk.
Speaking of charger, the excellent design of 10X charger is a real unsung feature if you have spare batteries. It combines the best of both world - charge the battery alone or with the light.
Alan