I'm running my Reo Grande today with 2 x AW 3.0V =6V and let me tell ya something, this box is a monster vape at 6V and packs one helluva punch of vapor & Flavor, it's the first time I have tried this and I don't know what has taken me so long but if any others haven't it's a total must to get your Grande 2 of these AW 3.0V Batts in fact I would recommend more like 4-6 of them because your going to really like it at 6V.. I also have some XHV Attys and am running it at 7.2 and its also an amazing vape. Mechanical or not this Box will keep paces with the best of those VV Boxes with the right set up of Batts and Atty's and as far as its structure no other Box Mod is as strong and can take a beating as much as the Reo Grande, I'm liking mine more and more everyday I use it. I highly recommend this unit to anyone considering a new Mod purchase.