My car's battery was dead due to Covid-19 (the good thing is it is not contributed to CDC's data tracker). I did a quick research and bought this Megawise jump starter. I'm not an expert, the reason I chose Megawise is because of "ADVANCED PROTECTION & UPGRADED SECURE CLAMP". Maybe other products also did this, I'm not sure. When this product arrives, I first charged it with USB cable. To be honest, I don't know how long it takes to fully charge, I left it overnight. The next day I used it on my car. My car's battery's negative pole is covered by a plastic piece (like a pipe), and people said they usually jump start this kind of car using the positive pole and the common ground. Unfortunately, this means the jump start cable is not long enough to reach the common ground. I checked other jump starter brands, it seems that the cable length is the same (about 21inch long only). The good thing is it's not that hard to remove that plastic piece. Finally, I connected the starter with the battery. When it connects to the negative pole, it sparks. I wish the cable can be longer because somebody said if connecting to the common ground it won't spark on the battery. Anyway, after connecting the starter, I heard it has a clicking sound, like a relay, and the LED shows the voltage is varying. Then I tried to start the car's engine and it works immediately. So overall, this product is easy to use, with LED display, and a portable bag. Again, I wish the cable can be longer, but maybe the length is standard. I found other brands may come along with car charger and wall charger, that's why they are a little bit expensive. I don't care. As long as it can be charged and can start a dead car easily, and the price is affordable, that meets all my expectations. The history of using another car to jumpstart is gone. Thanks for offering this great product.