AGM and EFB technologies are similar to each other, the main difference is the electrolyte used. In the first case, liquid is used, the fiberglass acts as an envelope. This option does not spill at all.
EFB batteries offer improved cyclic durability and better charge acceptance. Therefore, they withstand frequent engine starts and long periods of inactivity.
AGM Batteries Absorbent Glass Separator, valve regulated in the seal, spill proof.