The CTEK Comfort Indicator uses a simple 'traffic light' system to show the state of charge of your battery. A flashing green light shows that the battery does not require charging. Orange means the battery should be charged to avoid harmful acid stratification. A red light warns that the battery is discharged to a point where sulphation (the main battery killer) is occurring and also that the vehicle may be in danger of not starting.Clamp type: for quick connect on various batteries. Ideal for workshops and showrooms. 150cm cableCTEK chargers equipped with comfort plug can be connected directly to the Comfort Indicators if charging is required (XS and MXS models)