Gravity GMSCABCL01 Microphone Clamp for Guitar and Bass Cabinets

This is a microphone clamp for mic placement on guitar cabinets, bass cabinets, and combo amps.
The clamp section expands and contracts with a spring, allowing it to be securely attached to the side or top of the cabinet body. The arm allows for mic placement in your desired position. Compared to traditional boom-type microphone stands, this product allows for space-saving and precise mic placement.

https://watanabe-mi.jp/gravity/item/item-195/