All instruments are made with Shellopan shells and Ayasa.
All instruments in 2018 are made from Ayasa shells.

All instruments are completely nitrided. Top and Bottom.

external 550mm, internal 530mm, high 280mm –
starting thickness before deepdrawing 1mm

Godan instruments are very stable you have to hit pretty hard(not recommended) if you want to de-tune the instrument. The instruments are pre-played extremely loud to check stability (only aloud by the builder, players are prohibited to do this) The instruments are also temperature tested multiple times in the process so that we are sure the instrument stays in tune on room temperature. Even if the instrument has been in the sun and gets detuned by hot wheater it wil be back in tune when the instrument cooled down back on room temperature.
Even though the instruments are stable always treat the instruments with respect.