Is a VRLA battery the same as AGM?

The VRLA (Valve Regulated Sealed Lead Acid)battery is the most popular reserve power design because the electrolyte is captive, preventing it from spilling even when the case is punctured. VRLA batteries are considered "maintenance free" and require no addition of electrolyte or water. Styles of sealed VRLA batteries include front-access telecom cells as well as high-rate UPS replacement batteries for Liebert, MGE and Powerware among others. General purpose SLAs are also produced for emergency lighting and other applications.

VRLA batteries are commonly further classified as:

AGM Batteries

Absorbed glass mat (AGM) battery - has the electrolyte absorbed in a fiber-glass mat separator.

Gel Batteries

Gel battery - "gel cell" - has the electrolyte mixed with silica dust to form an immobilized gel.