What is the material of this key cap, why it is so expensive？

The material is zinc-plated aluminum alloy ZNAL903, which is more expensive than aluminum alloy and other alloys.

The key cap is designed and made by three-dimensional relief process, each one is colored individually by worker and has complex technology.

What is the height of this key cap? what position should be installed?

The lowest position of the key cap is about 0.9CM. It is close to the R4 height of the Cherry original factory, and the total height is about 1.1cm after add surface stereoscopic pattern. It is close to the OEM R4 key cap height. It is suggested to be installed in the ESC, F area and the main key position digital area.