Zaunkoenig M2K Gaming Mouse @ TechPowerUp
 

Exclusively intended for fingertip grip, the 24 g Zaunkoenig M2K is the world's lightest gaming mouse. With a carbon fiber body, Japanese Omron main button switches, and driverless 8000 Hz polling rate, the M2K is built for the lowest latency possible without compromising on anything.

https://www.techpowerup.com/review/zaunkoenig-m2k/