WatchLOI works on almost every up-to-date browser on almost every modern device, so if you have a reasonable specification tablet or computer that is less than 3 years old, it will probably work.
In order to stream WatchLOI on your device, you will need a strong, stable broadband internet connection with a minimum of 2MB to stream at the lowest bitrate of 240p (a mobile 3g, 4G, LTE, etc. internet service will probably be too weak or too variable to give a good service) and a ping of less than 100m/s. The higher your download speeds, the better the quality your streaming video will be. You should achieve HD quality (720p) at 5MB.
You will need a computer, tablet or mobile smartphone device (such as an iPhone or Android smartphone), and it should be running a compatible web browser such as Chrome, Mozilla Firefox or Safari.