From Luftverk:
This is the STELVIA XSP, an "Injection Machined" yoyo which is a technique that achieves that classic yoyojam over molded bearing seat feel but the quality of a premium machined aluminum. It is first injection molded into a large plastic blank then the profile is completely CNC machined. This is an independently funded project that I have dumped a monumental amount of money into, so it's pretty surreal to see it completed!
This variant dubbed the Stelvia "eXtreme Stability Plastic" has been designed to mimic how a metal yoyo feels based on rotational intertia values. A combination of heavy prototyping and computer simulation has helped achieve a metal like feel while keeping the soul and fun of a plastic yoyo.
Specs:
Diameter: 59mm
Width: 48mm
Weight: 67.54g