Review on Jump-Start Your Car With Ease: Portable 2000A Battery Booster For Gas And Diesel Engines, 20000MAh Power Pack, USB Quick Charge 3.0, And LED Light by Joseph Anderson

I ordered this to have in my spouse's vehicle---as a backup to jumper cables---should no vehicle be available for a jump. What sold me primarily is the claim that this will hold a charge for a year! While I have not used it to jump vehicle yet I came to find that this is also a battery backup for anything that plugs into a car lighter or a USB port. I have used it for this-----going through the manufacturer recommended cycling of new battery----and it's worked great! Appears to be a really cool device and smallish item to add to the safety/emergency kit.