blay buckle

It is the rider belt owned by Kenzaki Kazuma.
Normally it is just a buckle, but when the Rouse Card "Change Beetle (Ace of Spades)" is set, a belt appears and is attached to Kazuma's body.
Next he pulls the handle on the right side, the buckle turns over (a “turn-up” sound is heard), and a energy barrier named the “Orichalcum Element” appears. Finally, when he passes through this barrier, he transforms into Kamen Rider Blade.