Must have for $6!!!
Super bright display, almost too bright. Very quickly allows you to test battery voltage. Tells you All Voltage, then goes through each cell one by one in just the right amount of time. It is roughly the size of the now old USB drives and come with a slide on cover. I sometimes get my batteries mixed up especially new ones I haven't labeled. I can just pop this on really quick to tell what is what in a matter of seconds.to sort my lipo bag. I also use this with new model setups every couple of minutes to determine a decent flight timer. No regrets on this purchase.