Terms of Use

Last updated: September 2026

1. Scope

These terms govern the use of the iOS app "Sylph" provided by Martin Rost, c/o flexdienst – #20426, Kurt-Schumacher-Straße 76, 67663 Kaiserslautern, Germany.

2. Agreement

The app is distributed exclusively via the Apple App Store. By downloading you accept these terms and Apple's End User License Agreement.

3. One-time purchase (Sylph Pro)

  1. The app is free to download and includes free features (Box Breathing). The full feature set (“Sylph Pro”) is unlocked by a single in-app purchase. The price is shown in the App Store before you buy (currently $9.99; regional pricing may apply).
  2. The purchase is processed through your Apple ID. Your contracting party for the purchase is Apple (Apple Distribution International Ltd.); the Apple Media Services Terms and Conditions apply in addition.
  3. This is a one-time purchase with no subscription, no term and no automatic renewal.
  4. The purchase can be restored on all devices signed in with the same Apple ID (“Restore Purchases” in the app). The purchase is tied to your Apple ID and cannot be shared with other Apple IDs.
  5. Refunds are handled exclusively by Apple under Apple’s terms.
  6. Right of withdrawal: For digital content, the right of withdrawal expires if, before the end of the withdrawal period, you expressly consented to performance beginning and acknowledged that you thereby lose your right of withdrawal (Section 356(5) German Civil Code, BGB). This consent is obtained during the App Store purchase process.
  7. We reserve the right to change prices for future purchases; purchases already made are not affected.

4. No medical advice

Sylph is a wellness and mindfulness tool, not a medical device. The included breathing techniques do not replace medical or therapeutic treatment. Consult a physician before starting intense breathwork (e.g. Wim Hof), especially during pregnancy, with respiratory or cardiovascular conditions.

5. Availability

We aim for continuous availability but do not guarantee it. Maintenance or technical outages may occur.

6. Intellectual property

All content (code, design, text, audio, logos) is protected by copyright. Apple trademarks (App Store, Apple Watch, HealthKit, Liquid Glass) are trademarks of Apple Inc.

7. Liability

We are liable without limitation for intent and gross negligence as well as for damage to life, body, or health. Otherwise liability is limited to typical, foreseeable damage.

8. Governing law

German law applies, excluding the UN Convention on Contracts for the International Sale of Goods. Consumer protection rights of the country of residence remain unaffected.