Silicone Band Protective Case For Polar M430 M400 Sport Watch Strap Bracelet+Protector Shell Cover For Polar M400/M430 Hot Sale|Smart Accessories| - AliExpress
Amazon.com : QGHXO Band for Polar M400/M430, Soft Adjustable Silicone Replacement Wrist Watch Band for Polar M400/M430 Watch (Black) : Sports & Outdoors
Polar M400 review: A feature-packed GPS running watch that can also track your steps and sleep - CNET