Yes, the device can measure radioactivity. It is a Geiger counter that can recognise gamma, beta and X-ray radiation. The measured values are recorded using a Geiger-Müller counter tube and can be displayed in various units such as μSv/h, μGy/h, mR/h, cps and cpm.
However, it should be noted that the information provided is not directly from Siwa, but from a similar product called JT-RAD01 from Joy-it. If you need specific information about a product from Siwa, I recommend consulting Siwa's official website or documentation.