This is an E-flite 1S, 500mAh, 25C High Current LiPo Battery Pack with UMX Connector. This battery is a direct replacement for the Blade 180QX and 180QX HD quadcopters.
Tuesday, May 12 2020 (10 months ago)
E-flite 1S 25C High Current LiPo Battery Pack w/UMX Connector (3.7V/500mAh)
Purchased along with the Blade Inductrix HD FPV RTF Ultra Micro Electric Quadcopter Drone. Dinged one star because they appeared to be matched to the original battery, but they are not - smaller in dimension and capacity by 50 mAh. And I have yet to try them out because the drone was faulty and had to be exchanged.