This is a decent mod. Two 18650 batteries means it doesn't need to be charged every day.
The reason for the 4 star review is bc of the owners manual. I found it confusing.
I can’t turn the brightness of the screen up so I can barely see what voltage it’s at. The back door is slightly adjar and ends up catching on my pocket. And every once in awhile I have to take the batteries out because nothing happens when I push the buttons. Doesn’t light up or turn on or anything so I end up doing the battery removal constantly. Maybe I got a lemon.