High sound speed super hard material Technica Hard of space technology. Micro Vickers Hardness 400 or more. Technihard having a surface hardness not to be a file is a special processing aluminum material born from NASA technology. It is light and has a high propagation speed, making it suitable for acoustic materials. As a structural material for the head shell, arm pipe, stabilizer etc., it realizes strength, durability and high sound quality which can not be obtained with ordinary alumite.