As others have pointed out the battery in the ST16 is a 1S 8700mAh with a EC2 plug. I ran a discharge curve on it (see below) and didn't expect to see what I did. I initially set the discharge cutoff to 3.2V, then reduced it to 3.1V and then had to reduce it again to 3.0V because I was not seeing the knee. Even at 3.0, the knee was just starting. Could have set it lower, but decided not to push the battery. Most Lipo's are into the knee at 3.2V and heading due south at 3.0V. This battery seems to hold up really well. I got an IR of 38mOhms.