I am using a new RX200S with the July 4th released 4.10 firmware and easily connect my 24.5mm diameter TFV4 Subohm Tank on the 510 pin connection. It's no problem for me. It's reading .4ohms as it should for my TF-S6 Sextuplet coils which are part of the Smoktech Cloud Chaser Coil series the "familly" and I've been hearing horror storied about people burning their lungs because of high wattage and/or high temp vaping. Now that my E-liquid is trusted (I trust the ISO self-regulation) for safety, this is something new those against the vaping industry can use against us. And believe it or not, I think certain coils, especially basic Kanthal or VW coils, shouldn't be able to harness such power as to harm a user's lungs from extreme temperature due to wattage and definitely prevent TC coils from harming lungs in this matter. I know people make their own coils, this is done at their own risk, but manufacturers like Smok and their TFV4 quadruple coils are too hot at higher wattages. I'm using the best coils I've tried which are .4ohms yet the vapor production is cooler and can max out at 100W. I use 85W and make more clouds that the quad coils did for me back when I prefered them. These are the perfect coils. Anyway I went off on a tangent. It's best to charge your batteries with an external 3-bay or 4-bay charger but in a pinch on a rare occasion it's gotten my device up and going for the time being (using the internal charging via usb) I didn' notice a diference except perhaps more efficient battery use and longer life with the latest update but I'm not a TC user so it might have other features updated, cannot comment on it. Overall I spend $44.99 on it and have never been happier. LG HB4s are appropriate as well as a spare LG HD2 set of 3. I feel a faster ramp up without a blast which leads to dry hits sometimes with some devices. It's perfect. It's solid and I just love the way a full TFV4 tank size fits on it. I use other tanks but I bought another TFV4 for it since my old tank broke. I use a Stentorian Steam Engine as well. Those two are my favorites. But it's flawless and affordable. Get yours. I didn't think I'd like it but I do. try one.