Seiko 6138, 6139-310.611, Balance, complete

• SEIKO original balance in very good used condition.
  

• Seiko part number: 310-611

• Fits calibers:
• 6102A, 6105A, 6105B, 6106A, 6106B, 6106C, 6109A, 6110A, 6117A, 6117B, 6118A, 6119A, 6119B, 6119C, 6133A, 6138A, 6138B, 6139A, 6139B
  

Technical data: SEIKO 6138A

• 21 jewels, automatic wind, chronograph, 60 s, 30 min, 12 h counter, day-date.
• S: = 27.0 mm.
• H: = 8.0 mm.
• N: = 21.600 A/h.
• Power reserve: 45 h.

Versions:

• 6138A:
• 6138B: modified switch mechanism.
• 6139A: without 12 h counter.
• 6139B: without 12 h counter, modified switch mechanism.