Hard to tell in the photos, but the cooling spike pattern, is an actual Vigreux design, tight 3 spike rings that point down toward the vapor source to absorb more heat. Mine is also flawless all around, a perfect Zion stem... The style is similar to those nomad cooling stems that mistvape sells too.
The long xl8r does not have that complex of a spike pattern, they are much larger, just two directions parallel to each other, so more air can go around them, and it's only five six spikes... Remember RBT had xl8rD briefly, that incorporated more flat fin style cooling spikes, like the drydrotube (and also rotated their direction full 360° instead of just parallel) which is also superior to the standard spike style, though more involved to produce... And Lamart's spiked cooling stems are yet another different design style.