Joy Fast shift knobs are made of mirror-polished Stainless Steel.
They are available in three sizes: super-short, short, and long.
The super-short shift knob is 60mm tall and weighs 297 grams (.65 pound).
The short shift knob is 80mm tall and weighs 408 grams (.90 pound).
The long shift knob is 95mm tall and weighs 436 grams (.96 pound).
All have M10 × 1.25 threads for Miata shifters (as well as most other Mazda models).