Picked up one of these yesterday.
They're wifi so the battery will only last 6 months according to Lenovo. Good solution if you don't want to worry about getting a Zigbee or Z-Wave hub.
These are just rebranded a Tuya Wifi-101 so it works with the Smart Life App. Looks like most of the reviews are to do the delayed notifications, the terrible instructions (took me 30 minutes to find the reset button), and the limited functionality with Google Home (it can only really tell you if a door/window is open or not).