The extra surface allows you to keep your thumb on the left side of the saxophone shaft. Made by hand with the help of machines and experience.
The item is intended rather for people with long fingers. 
Finishing - polished or raw brass, choose please what you want.
For the older saxophones, which have a soldered not screwed rest, I offer a base that must be soldered to the body, see pictures 5 and 6. Such a base costs £ 9.99 more.
After paying, let me know what brand of saxophone you have and what thumb rest position do you prefer: | or \ ?
There is no / position for this product.