i've used crappy 18650 chargers that have definitely damaged the 18650s used on them

my only other option before buying this, was chargine via the USB through feature on my cloupor mini (yes i know some have had mixed results & mostly negative comments regarding this)

when this arrived i noticed batteries charged with this retained charge longer!

i also noticed when "fully" charged 18650 batteries charged by my cloupor, other crappy charger or 18650 powerbank were inserted into UM20 they were never truly fully charged?!

not mentioning which ones but some fully charged batteries consistently showed up on the UM20 as 91%-93% and while the worse offending ones charged up to only low 80%

the UM20 is not a rapid charger but its not the slowest 18650 i own either
best build quality with well thought out design will delight whenever used

can charge two 18650s regardless of current charge while allowing usb charge through of another device eg smart phone, tablet, powerbank

you can also specify which has priority of charging the batteries or the usb device

the usb charge through socket also doubles up as usb cable lock that allows cable management, usb cable can wound up neatly for OCD users and ensures cable always there & wont be forgotten by user

on a side note, the UM20 works better when used with "Fast Charge Micro-USB High Speed Charging Cable" SKU1355900 than with nitecore cable

my only regret after using this for a fortnight is the fact i only ordered one when i should have bought two or three! buy this & never charge 18650s on anything else!!!

отличная зарядка, заряжает быстро и равномерно, заряд показывает правильно

With a 2A usb wall plug it's one of the best speed/size/price ratio around. Waaaay better than my old I2, but remember you can't charge nimh with that charger. It charges 2 Samsung 25R 2500mAh within 3 hours

эта сучка не хочет заряжать два аккума одновременно. использую блок оригинальный самсунговский на 2,5 ампера, а этот пидорас все равно остановливает зарядку одной из батарей. нахуй не берите. возьмите лучше сошайн. выкинул зарядку на помойку, ибо нехуй

Great compact charger - I use this and/or my UM10 as a travel charger.
Would be a great primary charger for someone with few batteries.

Very good device for li-ion and imr batteries. But its sad that it can only activate over discharged protected li-ion batteries.

Got this one as a backup. Its a good charger.

I bought this for two reasons : small travel charger, and also a solution to charge my 10440 batteries without overcharging, as it is the case with my other nitecore charger (0,5 Amp is nearly two times the capacity of these batteries). All I need now is to find my old 500 mA/h phone charger, and connect an hungry phone and two batteries, and switch on usb priority, to get a "small" charging current for the batteries.
I just tested with a stronger phone charger (1 A/h) and it works quite well, but too fast for the 10440.
Anyway good item.

Super, I'm very pleased. The battery charger product is a great, 10 star seller.

this article no longer works with 10 uses...it is very bad quality...don't buy it.