Description Vetus maintenance free battery, 125 Ah, VESMF125 These batteries are suitable as starter- and service batteries.The SMF (Sealed Maintenance Free) marine battery series. A sealed VRLA maintenance free battery which never needs to be refilled. The lids on this series of batteries internally re-circulate any gas that occurs during use or charging. The battery construction is based on the use of leadcalcium plates , which yet further reduce the water usage. Some models are equipped with a “magic” eye which indicates the state of charge.