The Beijing SB18 series is a 19,200(?) bph, 17 jewel, 3/4 plate hand winding movement, with hacking and hand-winding. It is based on the Miyota 8200 series, with the automatic winding deleted, and a good number of other changes. The original version used the same mainspring barrel retention mechanism of the auto-winding mechanism.
The initial version SB-18 was replaced by an improved version B18-6 with the following main changes:
- The seconds (fourth) wheel moved from 4/5 o'clock to 6 0'clock position, allowing direct drive of the seconds hand, avoiding the "jumping seconds" effect.
- The winding mechanism is replaced by a classic he classic hand-winding barrel retention mechanism, improving the reliability and feel of the hand winding.
- Support for date function.
In addition to many minor changes, the B18-6 can be regarded as a design of its own.
Some specifications of the B18-6:
- Number of jewels: 18
- Diameter 26mm
- Thickness 4.01mm
- Time-keeping duration 42 hours
- Precision -10～+25 seconds
- Number of parts 158
- Features gold chaton; single swan neck fine regulator