14mm ground joint
Perfect vortex and bubble dumping function
3 seed perc
The difference between these and the BTK is the added section of fab holes in the middle sphere, adding extra diffusion.
Extra thick glass in all places, this version of the BTK is slightly improved from the last. The main changes are the percolator size being reduced by 20% as well as an adjustment to the drain. The function on these is very smooth and light for a recycler.