The SchumacherIP-1850FL Instant Power features:

Jump Starter On/Off switch – completely shuts off internal battery at clamps for added safety eliminating accidental shorting of clamps and battery drain.
Convenient, built-in charger transformer – for automatic charging of internal battery. Just connect an extension cord to the plug in the back to recharge. Charging LED will glow.
Easy-to-read battery status LEDs – tell when internal battery is at Full Power, 75% Charged or 50% or Less. An audible low-battery alarm beeps when battery is at less than 50% charge.
Charging and Charged LED indicator – to help easily monitor the charging of the internal battery.
Heavy-duty, copper jaw, 300 amp, metal clamps – for solid connections to top and side post batteries.
#4 gauge, 28-inch cable – stays flexible in the coldest of temperatures.
Reverse hookup protection – safeguards car battery, computer and Instant Power from damage if the cables are connected to the wrong terminals. An audible alarm warning sounds when clamps are reversed or touched together.
Durable, rust and corrosion-proof, one-piece construction, polypropylene case – resists fuels and solvents.
Compact size – easily stores in any position