Rechargable Valve-Regulated Lead-Acid Battery This is more commonly known as a sealed battery (SLA) or maintenance free battery and can be used in a range of hobby projects, Kids ride on car, toys and electric bikes. It is also frequently used as a back-up power source for home security systems in the situation of a blackout. It also last longer in a situation when the main power source is cut off compared to its cheaper counterparts. If you are looking for a great solution to your backup power needs,used in large portable electrical devices, off-grid power systems and similar roles this is the choice for you.