Ajazz AJ199 4K @ TechPowerUp
 

The ambidextrous AJ199 4K comes with PixArt's PAW3395 sensor and polling rates of up to 4000 Hz in wireless operation. Huano switches are used for the main buttons, and despite weighing no more than 63 g, a massive 900 mAh battery is used, promising up to 300 hours of battery life.

https://www.techpowerup.com/review/ajazz-aj199-4k/