Well I was sort of disappointed when I went to use my favorite atty the Ikenvape i06 on my SS GGTS and the drip tip wouldn't fit through the top cap hole.The i06 looks like a 306 but has a diameter larger than a 306 but smaller than a 510.This makes them bigger in diameter than a 510 when the drip tip is put on.I ended up using the atty protector sleeve they come in and they fit in the top cap and seal air tight.It looks sort of stupid with a plastic orange cap sticking out my GGTS but it's only temporary until I find another solution.The flavor these attys give went from great to incredible because of the air control on the GGTS.I have been vaping COV Butterscotch on a 3.5 ohm i06 at 6 volts for a few hours now and just can't stop.I hope I can find a way to make this atty work in my UFS when it gets here on Monday.Give this atty a try if you guys haven't it has incredible flavor.