The new Model 4001, from SOLAR, delivers power, convenience and optimal safety to heavy-duty jump starting. It features 12/24V operation, accommodates two (user-installed) batteries up to Group 31 size, extra-long 10’ 1/0 cable leads and automatic recharging of its on-board batteries. The 4001 adds numerous safety features to its package of power and convenience, for optimal operator and vehicle protection. The 4001 will not allow unit engagement until a proper battery connection is made. If a reverse polarity connection is made, there is no risk of sparking (dangerous) or damage to electronic vehicle components (expensive), since the clamps are not powered. The unit also compares the voltage selected on the unit and the voltage of the vehicle, engaging its power only if the two are compatible.