LEGAL
Terms of Service
EFFECTIVE 18 FEBRUARY 2026
1. Introduction
Welcome to MustDuo LLC. These Terms and Conditions govern your use of the MustDuo fitness application and any associated devices (the “Service” or “Tracker”). By accessing or using our Service, you agree to be bound by these Terms. If you do not agree, please do not use the Service.
2. Eligibility & Account
You must be at least 16 years old to use the MustDuo app. Users under 18 must comply with applicable local laws, which may require parental consent in certain jurisdictions. The Service is available only in regions where we offer hardware shipping and app support, as specified on our website. You are responsible for maintaining the confidentiality of your account credentials and all activity under your account.
3. Use of the App and Tracker
Our app offers workout plans, tracking via the MustDuo tracker, historical analytics, progress charts, fitness challenges, and leaderboards. Users may input personal health data or rely on data collected by the Tracker. The Tracker collects movement patterns via a 6-axis IMU and detects exercise reps. This data, along with user-input health information, is used to personalize your experience. We may store and analyze this data to improve the Service. For details on data collection, usage, and sharing, see our Privacy Policy.
4. Fitness and Health Disclaimer
The MustDuo app and hardware are not medical devices and do not provide medical advice. Exercise involves inherent risks, such as injury or strain. Always consult a qualified healthcare provider before beginning any fitness program, especially if you have pre-existing conditions. Use the app and tracker at your own risk.
5. Subscription, Purchases, and Refund Policy
The app operates on a freemium model with optional paid subscriptions and in-app purchases. Subscriptions and digital purchases are non-refundable except where required by law. To cancel a subscription, contact support@mustduo.com. Platform-specific purchases (e.g., Apple App Store, Google Play) must be handled through the respective app store’s refund process. Hardware purchases are refundable or replaceable within 30 days if defective. To request a refund or replacement, contact support@mustduo.com with proof of purchase. You are responsible for return shipping costs unless the defect is manufacturer related.
For customers in the European Economic Area and the United Kingdom, you also have a statutory right to withdraw from a hardware purchase within 14 days of delivery, without giving a reason, in addition to the 30-day defect window above. To exercise this right, contact support@mustduo.com within 14 days of delivery. You are responsible for return shipping unless the item is defective.
6. Hardware Terms
You own the MustDuo tracker upon purchase, unless provided under a lease or promotional agreement (details specified at purchase). We offer a limited 1-year warranty covering defects in materials and workmanship. This does not include damage caused by misuse, modification, or accidents. To make a claim, contact support@mustduo.com with proof of purchase. The Tracker is not a medical device. We are not liable for indirect or incidental damages.
7. User Behavior Rules
Users must not engage in illegal, unauthorized, or harmful behavior within the app, including but not limited to:
Reverse engineering the app
Tampering with the tracker
Redistributing MustDuo content for commercial use
Violating applicable laws and platform terms
Misuse may result in suspension or termination without refund. Users must also comply with applicable laws and platform terms.
8. Intellectual Property
All content in the app, including logos, fitness materials, and software, is owned or licensed by MustDuo LLC. You may not reproduce, modify, or distribute our intellectual property without written permission. To request usage rights, contact support@mustduo.com.
9. Limitation of Liability
To the extent permitted by law, MustDuo LLC is not liable for any injury, damage, or loss resulting from the use or misuse of the app or tracker. This includes, but is not limited to, indirect, incidental, special, or consequential damages (e.g., lost profits, data loss, personal injury). Users accept all risks related to exercise and acknowledge that MustDuo does not monitor or verify the accuracy of workouts or user-generated input.
10. Arbitration and Dispute Resolution
You agree to resolve any dispute with MustDuo LLC through binding arbitration under the American Arbitration Association (AAA) rules in California, unless agreed otherwise. You waive the right to participate in class-action lawsuits. Each party bears their own costs unless the arbitrator rules otherwise. This clause is governed by the laws of the State of California. For details, see www.adr.org.
11. Termination
You may terminate your account at any time. We may suspend or terminate your access if you violate these Terms. Terminated users are not entitled to refunds. Post-termination, your data will be retained for 30 days before deletion, per our Privacy Policy.
12. Modifications to Terms
We may update these Terms from time to time and will notify you of material changes (e.g., changes to fees or user rights) via email or in-app notice at least 30 days before they take effect. Continued use after changes are posted constitutes your acceptance of the revised Terms.
13. Third-Party Services
Our Services may rely on third-party providers for functions such as cloud hosting, payment processing, analytics, and data management. These providers operate under their own terms and privacy policies, and your use of the Services constitutes acknowledgment of such third-party involvement. The app also integrates with Apple Health and Google Fit, allowing workout and fitness data to be shared to enhance tracking and personalization. You consent to this sharing by enabling the integration. For details on what data is shared and how it is handled, please refer to our Privacy Policy.
14. Governing Law
These Terms are governed by the laws of California, USA, without regard to conflict of law principles. Disputes are subject to California courts, except for small claims eligible cases.
15. User-Generated Content
If you upload content (e.g., workout logs), you grant MustDuo a perpetual, royalty-free license to use it for service improvement and analytics. You represent that you own or have rights to the content and that it does not violate any laws or third-party rights.
16. In-App Purchases
In-app purchases are non-refundable and managed via the app store. If an in-app purchase fails or is defective, contact support@mustduo.com, and we may provide a replacement or refund at our discretion.
17. Free Trials
Free trials may be offered at our discretion. You may be required to provide billing information, and your subscription will auto-renew unless canceled before the trial ends.
18. Indemnity
You agree to indemnify MustDuo LLC from any claims, losses, or damages arising from your misuse of the Service or violation of these Terms.
19. Severability
If any provision of these Terms is held unenforceable, the remaining provisions will continue in full force and effect.
20. Contact Information
For questions, account issues, or refund requests, contact us at:
MustDuo LLC
23936 Old Pomegranate Rd, Yorba Linda, CA 92887, United States
Email: support@mustduo.com
