Polar M400 Watch Repair - iFixit

Polar M400 M430 Fitness Watch M400 Polar Strap Replacement - Silicone Wristband - Aliexpress

Polar M400 Watch Screen Replacement - iFixit Repair Guide

Polar Vantage M2 GPS Watch - Copper/Brown - 90085163

Hands-on: Polar's M430 GPS watch with optical HR

Polar Smartwatch - iFixit

SOFT MATERIAL: TPU silicone strap is flexible, waterproof and durable; protects from scratches, wear and tear.

Watch Band Compatible with Polar M400 / M430 - Watch Band Replacement Silicone S

Polar M400 review: A feature-packed GPS running watch that can also track your steps and sleep - CNET

Polar M400 User Manual

Screen Protector For Polar M400 M430 Premium PET Screen Protectors for Polar M430&M400 Sports Smart Watch Easy to Install - AliExpress

Polar M400 Watch micro-USB connector Replacement - iFixit Repair Guide