Not sure if you are referring to a specific charger, but the
mini usb charger on sale for $6 uses a silicone sleeve instead of threads. This means that it can charge any 3.7v battery. It works on my 901s and has been confirmed to work on the 510s, 801s, and other e-cig batteries. Some have reported that V4L's
other/corded usb charger works the same way... even though it does not have a silicone sleeve, the threads are further down and don't have to be engaged for a battery to be held in place and charged. You should read this thread:
www.e-cigarette-forum.com/forum/vapor4life/45296-sexy-lil-charger.html