All VETUS batteries are manufactured in the EU and are specifically designed for use in recreational and professional boating. The construction takes into account the changing demands placed on marine batteries. In winter, these batteries are not used for several months and are not charged during this time. Therefore, VETUS boat batteries have an exceptionally low self-discharge rate (approximately 3%) and can still be used after winter to start the engine. Throughout the season, the battery must also meet various requirements. It must be capable of delivering both small but constant loads as well as short, high loads, such as when using a bow thruster. The SMF (Sealed Maintenance Free) Marine Battery Series is a sealed and maintenance-free boat battery that never needs to be topped up. The design of the casing is therefore completely closed, except for a small pressure relief valve. The battery construction is based on the use of lead-calcium, which significantly reduces water consumption. Some models are equipped with the "magic" eye that indicates the battery's charge level. Lifespan is 7-8 years, charge/discharge cycles 350 -35%, self-discharge 3% per month, electrolyte liquid, plate material: lead-calcium, VRLA (pressure relief valve), suitable for series and parallel connections, transport-safe, maximum usage angle 55°, maintenance-free. Intended use: starting the main engine and generator, bow thruster, anchor winch, pumps, converting 120 or 230 volts. Battery deposit notice Germany: According to the legislator, we are obliged to charge a deposit of 7.50 euros including VAT in Germany if the end consumer does not return a used starter battery at the time of purchasing a new battery. The deposit will be refunded upon return of a starter battery.