The popular Hollow Hybrid feature a long taper, polished pin and solder pulled back the perfect amount.  That affords them amazing ink flow and just the right amount of flex and spacing between the needles to push these large liners in without damaging the skin.  Wanna get those bold lines you see on the internet in controlled, single pass?  Here you go!  These also work incredibly well for smooth black and grey shading small areas, as well as lining clouds, etc, as the polished long taper pins allow a finesse that a tighter liner cannot deliver.