# VO2 Flow vs Four by Four (fa7b3d)

The clearest difference is in-app purchases: Four by Four (fa7b3d) at none against VO2 Flow's 1. Four by Four (fa7b3d) also leads on ads (none vs shown). On price, device support and iOS requirement there is nothing between them.

Both are free to download. VO2 Flow sells 1 one-off in-app purchase. Four by Four (fa7b3d) asks for nothing beyond the download.

## The numbers

| Metric | VO2 Flow | Four by Four (fa7b3d) |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/vo2-flow-norwegian-4x4-timer/id6757104585/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 5 weeks | — |
| Monetization | Free with in-app purchases | — |
| Size | 25 MB | 44 MB |
| Requires iOS | **13.0** | 13.4 |
| Devices | iPhone, iPad, iPod | **iPhone, iPad, iPod, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [CHRISTOPHER DISCOTTO](https://appshunter.io/developer/1864553330) | [Bhavik Patel](https://appshunter.io/developer/1890740800) |

## What reviewers say

### VO2 Flow

[App page](https://appshunter.io/ios/app/vo2-flow-norwegian-4x4-timer/id6757104585)

This interval training app guides you through the Norwegian 4x4 protocol or allows you to create custom workout routines. It offers audio cues, haptic feedback, and music integration to enhance your training sessions. Track your progress with workout history and unlock achievements.

**Highlights:** Norwegian 4x4 protocol, Custom interval creation, Workout history tracking, Apple Music integration, Audio cues and haptic feedback, Achievement badges

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Upgrade | $4.99 | one-time |


### Four by Four (fa7b3d)

[App page](https://appshunter.io/ios/app/four-by-four-fa7b3d/id6766068267)

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is VO2 Flow free?

VO2 Flow is free to download, with in-app purchases available.

### Is Four by Four (fa7b3d) free?

Four by Four (fa7b3d) is free to download, with no in-app purchases.

### Do VO2 Flow or Four by Four (fa7b3d) have ads?

VO2 Flow shows ads; Four by Four (fa7b3d) does not.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*