Just to clarify K3vin's air hole mod. The modification the machinist did isn't side entrance holes as it first appears, as he drilled into the existing passages. Air still comes down the internal passages from the top and still has to make a essentially 90 degree turn to get into the chamber, his holes aren't drilled to the outside. What he's essentially done is move the entrances up higher in the chamber which may have a benefit to certain coil types. It does eliminate the adjustable draw, but if it works for him and he is happy (which no doubt he is), I say Vape on!