Heavy-Duty Rechargeable Battery: The VEVOR 12V 40Ah rechargeable deep cycle battery, with dimensions of 7.8'' x 6.5'' x 6.7'', stores a substantial amount of energy, extending the runtime of most light-duty electric devices. Note: Professional charging equipment is required during use to ensure battery security. No Maintenance Required: The deep cycle marine battery utilizes absorbent glass mat (AGM) technology, so no maintenance is required. Compared to traditional lead-acid batteries, it has minimal electrolyte consumption, avoiding the need for liquid top-up during use. Security & Durability: Our deep cycle battery is for secure usage. It employs AGM technology, enabling multiple cycles and a longer lifespan compared to common conventional batteries. Coupled with excellent conductivity, it minimizes power loss to ensure uninterrupted power supply.