The CT-1, known as the California Twin Beacon Ray, utilized a pair of what appeared to be a pair of 184 beacons on a Visibar. The 184 on the passenger side was a standard version Model 184, the one on the driver's side lacked a motor and instead had a forward facing, steady burn PAR-46 lamp and a rear facing PAR-46 connected to a flasher. The dome on the driver's side was a split color, with red to the front and amber to the rear. It was advertised in Bulletin 67, which had an effective date of March, 1970, printed May, 1975, so it was definitely available from 1970 through 1975. That's about all I can tell you.