6279Q595 Replacement Battery 1600mah for Apple iphone 3G
Seems to be a good battery during initial testing in the make-shift use to replace a poorly designed battery in an M-Audio 24/96 recorder.  Check for online instructions/guide on how to do the replacement AND add some trimming of the larger plug ends to make room for it in the present case.  And solder it in place and cut off the iphone connector.  Gives more recording time than original new machine.