Constant output mini plug-in charger. Plug it in to a nearby socket and fix the crocodile clips to your car battery to trickle charge it constantly whilst not in use. Uses very little power - 500mA. Because classics are only used occasionally, the lead acid batteries suffer internal corrosion whilst standing and gently discharge. If you've ever wondered by you are replacing your very expensive battery every couple of years, this is the reason. Especially true of electric start mowers too which sit all winter. 12V lead acid batteries only. Cable length 1.6m (just over 5ft). Fits UK style 240v/13amp socket. Ensure area is ventilated.