Seiko Calibre 1B21B Solar Radio-Controlled Quartz Movement

The Seiko Calibre 1B21B is a three-hand analogue solar quartz movement with radio-controlled time synchronization. It receives supported standard time signals to automatically correct the displayed time, combining solar charging with precise quartz timekeeping.

Its radio-signal reception system supports transmitters in Japan, China, the United States, and Germany. Automatic and manual reception modes are available, along with reception-result display, time-difference adjustment, and automatic hand-position correction.

The solar-power system converts light into electrical energy and stores it in a rechargeable secondary cell. When fully charged, the movement operates for approximately six months, extending to a maximum of approximately 18 months when power-saving mode is activated.

Product Specifications

Product Type: Solar Radio-Controlled Quartz Movement
Manufacturer: Seiko
Calibre: 1B21B
Time Display: Hour, Minute and Central Seconds
Calendar Function: No
Quartz Frequency: 32,768 Hz
Accuracy Without Radio Reception: ±15 Seconds per Month
Operating Temperature Range: −10°C to +60°C
Driving System: Stepping Motor
Power Source: Solar-Powered Rechargeable Secondary Cell
Power Reserve: Approximately 6 Months When Fully Charged
Maximum Duration with Power Saving: Approximately 18 Months
Radio-Reception Regions: Japan, China, United States and Germany
Automatic Radio Reception: Yes
Manual Radio Reception: Yes
Reception-Result Display: Yes
Time-Difference Adjustment: Yes
Automatic Hand-Position Correction: Yes
Power-Saving Function: Yes
Overcharge Prevention: Yes
Instant-Start Function: Yes

Radio-signal reception depends on the watch’s location, surrounding environment, case construction, antenna, solar cell, and correctly matched electronic components. The movement will continue operating according to its internal quartz accuracy when a radio signal cannot be received.

Please compare the complete calibre code, movement layout, hand fittings, stem position, dial configuration, antenna system, solar-cell assembly, case components, and movement holder with your existing watch before ordering. Professional installation is strongly recommended.

Package Contents

1 × Seiko Calibre 1B21B Solar Radio-Controlled Quartz Movement

Important: The rechargeable battery and solar panel are not included.

Seiko is a registered trademark of its respective owner. The trademark and calibre reference are used solely to identify the movement and its specifications.