The cthulhu 520 bridge/boro comes with the adapter.
Otherwise u can get the brijd (sp?) if u can get your hands on one.
Or u can buy a dovpo abyss pnp bridge, and figure out a way to make the bottom fit, (i believe u would need to put some sort of collar around the bottom of the coil to get the right diameter, iirc, either that or drill it out s little)
Edit-for the pnp coils u dont need a split tank i believe, my bad