Although having my Silver bullet, and Mako, I carry my 510 on a Eye glass Chain. It has 2 rubber eyelets so not to scratch my pv, but, also keeps it from slipping out of knot.
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I find mostly it's the liquid, most pg liquids doesn't give much vapor, vg on the other hand give off vapor galore like what you see mostly on youtube. Another added source of vapor is the voltage being used; 1.5,3.0,5.0,6.0