square key; heart-shaped key; chrome finish key with Night Brass Cube logo;

Night Brass Cube is a band which collaborates with Mr. Hiroshi Chu Okubo;

here is the link of the band: 

https://x.com/NightBrassCube

育てるドラムチューニングキー / 大久保宙シグネチャードラムチューニングキー

Many thanks to Mr. Okubo for his help in obtaining these keys and for his educational work; thanks Hiroshi!