This is a nice compact emergency battery jumper with some integrated safety features and built-in convenience of a USB charging function and flashlight. It has a nice, large, easy-to-read display and comes with a protective case. It's jumping functionality and safety features work well - you plug in the alligator clips, and an integrated tone and LED light tell you when you ahve connected it correctly to the vehicle battey. No problems there, it's fairly simple and anyone can follow the easy-to-read directions included. Unlike other models I have used, there's no physical lockout switch on board, it's just a power button to activated the LCD that shows capacity, charging status, and output, and a second soft button for the flashlight. The flashlight is a nice, large area at the bottom of the unit and is quite bright, in additional to various strobe effects.The reason I have knocked off a star is because of the claimed battery capacity of 20,000 mAh, or 20 Ah. You would be forgiven for expecting that to be the equivalent of an external battery for charging cell phones, earbuds, etc, bit it's not. Those battery banks have a single battery which allows an apples-to-apples comparison. I did not open the unit to look in detail, but I suspect this is a group of batteries that have been "added" to claim that capacity. While that's fine when it comes to jumping vehicles, it's not accurate for the USB charging functions. By way of an example (similar to another jumper I tried): I plugged my Pixel 6 (4600 mAh battery) into this booster with the Pixel at 86% charge, and the booster at 100% charge. If this were a true 20 000 mAh battery, it should be capable of charging the full Pixel 6 at least four times from dead to full. However, when the Pixel was at full charge, this battery was reduced to 69%, a drop of 31% capacity to charge less than 20% of a *much* smaller phone battery. The take home message is this: while this has the emergency capability to restore some charge to devices via USB charging function, you *cannot* rely on it as a regular external charger for other devices and are much better off buying a proper portable charging battery dedicated to that purpose.As a car jumper though, it's great, and tested fine when connected to my vehicle (in the sense that it properly connected and delivered charge; I could not test the actual voost as I didn't have a dead 12V vehicle battery kicking around). It's listed at $100 CAD at time of review with a 30% off coupon, bringing the final price to $70 plus tax which I think is a pretty reasonable cost for the quality of the jumper overall.