TechPowerUp posted a review on the G-Wolves HSK Pro 4K
A quote from the article:
Similarly to the Zaunkoenig M2K, the HSK Pro 4K is designed exclusively for fingertip grip. Despite weighing no more than 26 g, the HSK Pro 4K even comes with proper side buttons, along with PixArt's PAW3395 sensor, Zippy main button switches, and true 4000 Hz wireless polling.G-Wolves HSK Pro 4K Review