The NiCd (Nickel Cadmium) battery cells are the type that we have used since 1982. We buy the best No Memory high quality cells and build them into industrial strength workhorses. We are the only company who actually guarantees the flashes per charge and the only company with an extended pro-rate warranty.
The Small NiCd Battery, BSML is the lightest weight option and can work at high power like the other Batteries, it's just smaller so it will run out of power sooner than the bigger batteries. It's not unusual for photographers to prefer some smaller Batteries over a larger one, especially since you can switch them easily when one gets low.
If you use 200ws we guaranty 100 flashes per charge. If you use 25ws, that same battery gives you 800 flashes. Likewise, if you use only 400ws, you should expect 50 or more flashes from this little battery.
The NiCd Batteries all have a 48 Month pro-rate warranty on the cells. For the Small Battery, that warranty loses value at $1.50 per month for 48 months. In some cases, there may be a sale price that is a better value than the total pro-rate at the end of the warranty. There is a small labor fee to install the cells and new cells always start a new pro-rate warranty. The case and electronics have a Two Year warranty from when it's originally purchased.