I got this charger to use in a second vehicle that does not get driver that often and there have been time when I would go to use it only to find that the battery was dead. One function of this charger is the ability to trickle or maintain a charge on a battery over a long period of time, which is exactly what I needed. Its a 12v 15 amp charger capable of supporting standard lead acid, AGM and certain Lithium Ion batteries. When you first connect the charger to the battery it (before plugging it in to the AC) it will display the current charge and amp level. A single button on the top of the charger allows you to switch between the supported battery types. Once connected to AC power the display shows the battery type, the the level of charging in 10% steps and the output amps of the charger. The display stays lite for about 20 sec and then goes out. The charger is quite, no fans, so when the display goes out there is nothing that indicates anything is happening. This is the first complain I have with this device. It would be nice to have some sort of continuous indication that the charger is actually working. You have press the button on the charger to re-activate the screen to get that assurance. The second issue I have is because there is no fan in the unit, it get rather hot. The bottom measured 117 F and the top 110 F. I think a fan would help keep the temp down and probably help prolong the life of the electronics. My battery was about 60% charged when I put the charger on it originally and it took about 30-40 hours to reach 100%. After charging reach 100% the temp dropped down to normal. Now the charger should only kick in once the voltage drops, and the charging cycles should be very short. The package includes the charger, an easy to read instruction manual, the clamp type battery connectors and a connector that you can wire permanently to your battery for quick connects and disconnect for longer term battery maintenance. Overall I like this charger and feel its a good value for the money. I would not buy this type charger if you are looking for a quick charge, you will need a larger more beefy unit for that, but for trickle type charging and battery maintenance/repair this make a a good choice. With a few enhancements, like a cooling fan and always on charging indicators I feel this would be just about perfect.