# 107.9 COOL vs Krun

The clearest difference is in-app purchases: 107.9 COOL at none against Krun's 1. Krun's advantage is update cadence (every 3 days vs every 32 months) and iOS requirement (16.6 vs 18.2). On price, ads and device support there is nothing between them.

Both are free to download. Krun sells 1 one-off in-app purchase. 107.9 COOL asks for nothing beyond the download.

107.9 COOL ships an update every 32 months, Krun every 3 days. Both last shipped on October 24, 2026.

## The numbers

| Metric | 107.9 COOL | Krun |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[3.0 (2 ratings)](https://appshunter.io/ios/app/krun-spinner/id6757863339/reviews)** |
| Number of ratings | — | **2** |
| In-app purchases | **No** | Yes |
| Ads | Yes | Yes |
| Update frequency | Every 32 months | **Every 3 days** |
| Monetization | — | Free with in-app purchases |
| Size | 13 MB | 6 MB |
| Requires iOS | 18.2 | **16.6** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Apple Watch |
| Age rating | 4+ | 4+ |
| Developer | [Burt Broadcasting Inc.](https://appshunter.io/developer/1086723214) | [Shinichiro Eto](https://appshunter.io/developer/1864675097) |

## What reviewers say

### 107.9 COOL

[App page](https://appshunter.io/ios/app/1079-cool-fm/id1086723798)

**Features:** macOS Compatibility

**In-app purchases:** none


### Krun

[App page](https://appshunter.io/ios/app/krun-spinner/id6757863339)

Engage with a digital pinwheel that creates captivating optical illusions as it spins and slows. Customize shapes, colors, and speed for a unique visual experience. It's a simple yet mesmerizing tool for all ages.

**Highlights:** Swipe-to-spin pinwheels, Illusions appear as rotation slows, Shape, color, and speed customization, Unlock all content, Remove ads

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Unlock | $2.99 | one-time |


## Frequently asked questions

### Is 107.9 COOL free?

107.9 COOL is free to download, with no in-app purchases.

### Is Krun free?

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

### Do 107.9 COOL or Krun have ads?

Both 107.9 COOL and Krun show ads.

### Which is updated more often, 107.9 COOL or Krun?

107.9 COOL ships an update every 32 months, and Krun every 3 days. Most recently, 107.9 COOL was updated on October 24, 2026 and Krun on October 24, 2026.

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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.*