Features: Naos Raptor 20A, 120W dc/dc converter output voltage range 3.3v to 6v external 18A fuse external zener diode for low voltage cutoff of 6v external 2x22uF input capacitors dual 18650 batts This Raptor mod definitely has become my fave mod since getting it done last week - most power packed awesome vape beast I've made to date! It does hit hard for the voltage. I usually vape my 1.5 ohm dual coil RBA at around 5.1v and sometimes a little higher, but I get a comparable hit at 4.7v with this mod. When I took that first hit dialed in at 5.1v, I almost choked. holy moly I thought, so I dialed it down to where I get the same hit I'm used to. Same with the 0.8 ohm nano coil RDA - I had to dial that down too. During testing I attached a 0.3 ohm coil and ran it at 5v (83W and 17A) and both converter and batts (30A Sony 18650) handled the load aok - and no, didn't take a toke off that. The batts I've tested with this mod are the Sony 18650 30A, Orbtronic 18650 30A, the Efest 18650 30A, and the MNKE 18650 30A batts. I have the LG LGDAHE21865 2500mAh 30A batts (13mOhm internal resistance) on order and will be testing with those when I get them. The LG batts may change this, but so far the Sony batt is far superior to all that I've tested. It has the lowest internal resistance (12mOhm) of all the 30A 18650 batts and handles the load both input and output without so much as a blink all the way down to cutoff voltage of 6.2v unloaded (6v loaded). The Orbtronic (19mOhm internal resistance) gave hiccups around 6.6 volts and cut out at 6.5v unloaded (dropped to 6v loaded). With its higher mAh vs the Sony mAh, it did give a long vape time before cutting out, but that higher internal resistance is a hindrance. Both the Efest and MNKE had horrible horrible input/ouput voltage drops under load and cut out around 6.8v-6.9v unloaded (dropped to 6v loaded). I wouldn't recommend either of those batts for use in our mods. Input voltage drop varies between 0.1v - 0.2v with the Sony batts and 0.2v - 0.5v with the Orbtronic batts. Output voltage drop varies between 0.0v - 0.1v with the Sony batts and 0.1v - 0.3v with the Orbtronic batts. All done and getting ready to close er up... Takes 2, 18650 batts... yes - the batts are in series - I wired the batt contacts so both batts are oriented the same way... no confusion with which batt goes up and which batt goes down especially since both batt holders are marked with + at the top and - at the bottom... Displays input voltage... Displays output voltage... range 3.3v - 6v (the tolerances of the resister plus POT I'm actually getting 3.39v - 6.1v with this build) ... 109mm x 58mm x 31mm... Parts list: SoShine dual channel 18650 charger (fasttech) Naos Rapter (NSR020A0X43Z) 20A, 120W DC/DC Converter (digikey, mouser) Fire switch (PV5S64011) (digikey, mouser) 2x22uF capacitors wired in parallel (C3225X5R1C226K250AA) (many thanks to CraigHB for recommendation on the input capacitor) (digikey, mouser) or GRM32CF51C226ZA12L (digikey, mouser) 2x9A fuses wired in parallel (650-RGEF900) (digikey, mouser) 200 ohm POT (PT10MH01-201A2020) (mouser) Shaft for 200 ohm POT (JPEPL5012NE or 5116) (mouser) POT knob of your choice that accommodates the size of shaft you've chosen (if using a shaft, a knob is not necessarily required) 220 ohm and 7.5K ohm resisters, and 5.6v zener diode (various sites) Mini 3-position slide switch (on/off/on) (I used Apem TG39P000000) 1S-6S voltage reader (ebay) 2x 18650 batts (recommend 30A discharge rating) Wiring guide... I used 20ga for input/output/voltage reader, 22ga for the mini slide switch and POT... Note1: do not attempt this build if you are not familiar with battery safety and electronics safety. If you attempt this build, you do so solely at your own risk. Note2: if you do build this mod, do not bypass adding the external fuses - they protect you and the entire circuit from a potentially faulty or unstable battery. Note3: if you do build this mod, do not bypass the zener diode - it provides a safe voltage cutoff of 6v. Without it, the voltage will go all the way down to the converter default of 4.1v unless the batt's undervoltage protection kicks in - but you can't always rely on that. Note4: make note to switch batt positions at mid voltage range, or switch the lead batt to the non-lead batt after charging. Note5: currently, the only batteries recommended for use in this mod are the Sony 18650 US18650VTC3 30A 1600mAh batts (most preferred) or the Orbtronic SX30 18650 30A 2100mAh.