This is a IS20 ball bearing turbo chra/core with IS38 wheels.
The internal structure of this IS20 ball bearing is similar to G25 G30 ball bearing structure, which uses the latest G series ball bearing.
Turbine wheel: upgrade high flow GT30 9B wheel, cut into IS38 OE size, can fit into IS38 OE/STD turbine housing, no problem, no machining required.
Comp wheel: upgrade IS38 comp wheel, bigger than IS20 OE wheel.
PS: the only difference between IS38 BB CHRA and this upgrade BB one is the back plate.
Learn more from here:
CHRA IS20 G25 G30 BB upgrade with GT30 9B turbine wheel and IS20 OE comp wheel
Turbo IS38 G25 G30 ball bearing upgrade with GT30 9B turbine wheel and larger comp wheel
CHRA IS20 G25 G30 BB upgrade with GT30 9B turbine wheel and IS20 OE comp wheel
IS38 06K145722H turbocharger CHRA
Turbo CHRA IS38 GTX ball bearing upgrade bigger wheel