I could be wrong but it looks like it just plugs into the speaker jack and is activated by audio. I wish they would have explainrd it further in the description. I can't see me using my 396 or any other expensive scanner for just WX alerts.
After much scrutiny, I'd have to say no. It say on eht website that it is For use with Midlandreg; weather radio models WR100 and 300. With it being so specific, i'd say this is a proprietary setup. It uses 3 AAA batteries for setup. I'm sure there is some sort of digital trigger that activates it. It plugs into an alert accessory port on several alert radio by other brands than midland. Either there is an internal switch that closes when an alert is received that completes the circuit back to the light or it sends a small voltage to the light which activates a relay. Either way, it doesn't look like plugging it into your headphone jack is going to make it work. I did find a site that has them for $19. Maybe you can get one to try out.