So it arrived, took me a bit to get it set up (sorry Daniel). Using HE4's while the HD2's charge (might not even use them with this). For starters the mod's not stainless steel only looks like it. Except for the horned top it's smaller than a ERM, really strong spring in the 510. I wish the 510's body was higher than the mods top by a hair but oh well. Really liking it so far, I can't believe how small it is. EDIT: So I switched to the LG HD2's from the HE4's after comparing the sag during firing using the same atomizer 40/50 watts) and full charged batteries. Both batteries are new also. The HD2 dipped to 3.75 volts and the HE4 dipped to 3.56 volts . No sign of "weak battery", even put on my Aromamizer with dual clapton's @ 75 watts but of coarse the battery was full charge. It's going to work for the "test"