Eco Drive technology is fueled by light and it never needs a battery
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Product Description
Citizen Watch: Citizen Men's Tank Watch BV1040-55E is powered by Citizen Eco Drive movement, no battery change needed. Since we are an authorized Citizen watch dealer, your Citizen BV1040-55E purchase will be backed by a 5 year manufacturer's warranty.
Source:
http://www.citizenwatch.com
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