Gates makes these and calls them Cyclon. I don't like these batteries. They tend to be large and heavy. This is the basis of rating batteries in AH or Amp-Hours. This is a very simplistic way to look at batteries.
Batteries leak much faster under higher than room temperatures.
The more current that you draw or put into a battery, the less efficient it becomes. So, a battery which can supply 2 AH at a current of 0.1A may only be good for 1.5 AH at a 0.2A discharge. To charge them I use a trickle charger. Basically the output of a 20V transformer is rectified with a full-wave bridge rectifier. I select this to give 100 mA or 1 AH charge in aprox 12 hours and 50mA for a low trickle charge.