Features: 1) With economical and durable DC-DC high performance power switch inside 2) Protect against overcharge, overload and short cut 3) Safe and speedy 4) Stable function 5) Designed for the cars with the voltage of DC 24V 6) Only use it with the negative pole connecting to the ground 7) Avoid putting it under damp or high temperature conditions 8) Heat generation during operation, normally not exceeding 60°C, at normal indoor temperature Inner packing: Color or white box