I use the DB120 and the HolyStone units
Here is info
Holystone
US FAA Compliant Drone Identification broadcast Module Spare Parts for F11GIM, F11PRO, F7, V11, HS720, HS720G, Mini 4, Mini2 SE, Mini 3, Air 3, ATOM SE, HS720, HS720E, HS720G, HS600, HS720R
Holyton
Dronebeacon...