This is SPM (Super Precision Machine Cut) titanium series ball stud long neck type. Reve D have released the Φ4.3mm rod end ball (long neck type) that is used in the YD-2 series, etc. With their highly accurate cutting process using a lightweight/highly rigid titanium material.
The dimensions are optimal for areas where many spacers are used, such as Ackermann adjustment of slide racks, allowing the length to be adjusted without using too many spacers. The narrow neck design strengthened by the highly rigid titanium material extends the range of motion of the ball cup.
Additionally the smooth movement of the ball cup, which is a feature of this series due to the high precision finish, is inherited. You can expect a great improvement in driving performance as well as weight reduction. The beautifully finished product is also perfect for that superior look on your machine.