I recently purchased a BigWater Depin Air Purifier and downloaded the Android BigWater app. It will ask you for the Device ID in the app … use your email address you purchased the device with. This info comes from the BigWater admin folks. I asked about why the android app was not showing any rewards and this is there response

Please be assured that your rewards are being recorded on the backend and shall be duly credited to you. The next update version of the app will also have the provision for you to be able to see the rewards accruing on your wallet.

They aslo said a iphone app will out soon.

I do not see this project a big money Maker but I like what they are doing for the inviorment and I needed a air purifier anyway.. \

https://bigw.bigwater.io/product/bigwater-air-purifier/