The Renata 321 SR616SW Swiss Watch Battery is a mercury-free silver oxide coin cell/button battery with a long expiry date. Designed as a reliable and durable power source for watches, this battery is made by the reputable brand Renata. Ideal for replacing worn-out or expired batteries in watches, this unit offers a secure fit and consistent power supply to ensure accurate timekeeping. Perfect for watch enthusiasts and professionals alike, this Swiss-made battery is a high-quality component for maintaining the functionality of any timepiece.