Renata 399 (SR927W) — High-Drain Performance for Advanced Watches

The Renata 399 (SR927W) is a high-drain silver-oxide button cell designed for analog watches with energy-intensive features such as chronographs or alarms. Measuring approximately 9.5 mm in diameter and 2.7 mm in height, it delivers reliable bursts of power alongside stable continuous voltage.

Core Specifications

• Chemistry: Silver-oxide, mercury-free
• Nominal Voltage: 1.55 V
• Dimensions: ~9.5 mm × 2.7 mm
• Drain Profile: High-drain (W)
• Compliance: RoHS, mercury-free

Advantages

1. Supports high-drain features without voltage drop
2. Leak-resistant construction
3. Swiss quality for consistent performance
4. Low self-discharge for long shelf life
5. Mercury-free environmental compliance

Applications

• Chronograph-equipped watches
• Watches with alarms or lighting
• Small electronics needing bursts of power

Installation Notes

• Match SR927W specification before replacing
• Use non-metal tweezers
• Replace gaskets for water resistance
• Check polarity before seating

Conclusion

The Renata 399 (SR927W) is a high-drain battery that delivers Swiss precision, consistent output, and dependable performance for advanced timepieces and compatible electronics.