VRLA stands for valve-regulated lead-acid and is the designation for low-maintenance lead-acid rechargeable batteries. Portalac batteries are often colloquially called sealed lead-acid batteries, but they always include a safety pressure relief valve. A VRLA cannot spill its electrolyte (battery acid) if it is inverted.
VRLA Portalac batteries can be substituted in virtually any flooded lead-acid battery application (in conjunction with well-regulated charging), as well as applications where traditional flooded batteries cannot be used.
When an emergency happens, you need to be depending upon a highly reliable battery in your emergency lights from Portalac.