Unlike the chronographs that had one, two or three sub dials, the Bell-Matic was not very distinctive; the alarm indicator is on the rotating ring around the dial. The only real distinguishing feature is the extra button at 2 o’clock. This sets the alarm on when out and doubles as a quick set for the date when depressed.
Like all Seikos of the period the Bell-matic is self winding but the alarm spring is wound manually with the main crown.
The 4006 is a tough reliable movement that was produced from about 1969 until around 1977, this example would have been one of the last produced.
While in production, Bell-Matics were an elite, high-end offering (at the commercial end of the market), they where about 25% more expensive than the top end Seiko divers and about three times as much as a basic Seiko 5 automatic. Today only good examples are of interest but they are nowhere near the Seiko chronographs in popularity.