My first was a North American TR-1 that was bought from the JC Whitney catalog. Amazing that they still make them today: https://nasig.com/Asset/TR1-A.jpg
Not too bright, so I sold it and got the 121 Vitalite - good on the roof (if you didn't go too fast, those little magnets weren't the best) but too tall for the dash. Sold that and went to an FB2 with the mirror, which I still have in the basement.
I think this Vitalite was mother (doctor) first green beacon in the UK. Early 1980s. Incandescent and the bulb holder upside down? She swapped it out for a prem hazard gyrolaser with multiflash mirror as that fitted better on the UK car dash.
I gave my younger brother a gen1 Vitalite when he joined the VFD. Discovered in cold weather, it wouldn’t rotate dependably as the drive slipped. Cured that with a piece of ball point pen spring between the C-clip and platter to put downward pressure on the drive…still in my collection.
Ipreferred the fireball as it would stay on the roof better when “tossed” backward.
The Series A1's drive system was certainly not the best, that's for sure. Relying solely upon gravity to hold the platter to the motor's drive shaft was simple, but came with some reliability issues.