# Underlairs vs Zarko

The clearest difference is in-app purchases: Zarko at none against Underlairs's 3. Underlairs's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 17.6). On price, update cadence and ads there is nothing between them.

Both are free to download. Underlairs sells 3 in-app purchases, starting at $0.99 per month. Zarko asks for nothing beyond the download.

Underlairs ships an update every 3 weeks, Zarko every 2 weeks. The most recent releases landed on October 9, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | Underlairs | Zarko |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (7 ratings)](https://appshunter.io/ios/app/underlairs-focus-study-timer/id6755931983/reviews)** | — |
| Number of ratings | **7** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Every 2 weeks** |
| Monetization | Freemium | — |
| Size | 230 MB | 5 MB |
| Requires iOS | **15.0** | 17.6 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [John Jang](https://appshunter.io/developer/1857417631) | [Jaehoon Lee](https://appshunter.io/developer/1889076539) |

## What reviewers say

### Underlairs

[App page](https://appshunter.io/ios/app/underlairs-focus-study-timer/id6755931983)

Enhance concentration and memory with curated ambient soundscapes and a focus timer. Choose from unique 'Lairs' and track your progress to achieve deep work and productivity goals.

**Highlights:** Focus Timer with customizable durations, Beast Mode for continuous music, Ambient soundscape playlists, Background playback, Lock screen controls, Stats tracking for focus minutes and streaks, Minimalist design

**Features:** macOS Compatibility

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Premium | $0.99 | per month |
| Yearly Premium | $9.99 | per year |
| Premium Lifetime Access | $17.99 | one-time |


### Zarko

[App page](https://appshunter.io/ios/app/zarko-block-apps-win-focus/id6791000644)

**In-app purchases:** none


## Frequently asked questions

### Is Underlairs free?

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

### Is Zarko free?

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

### Do Underlairs or Zarko have ads?

Neither Underlairs nor Zarko shows ads.

### Which is updated more often, Underlairs or Zarko?

Underlairs ships an update every 3 weeks, and Zarko every 2 weeks. Most recently, Underlairs was updated on October 9, 2026 and Zarko on October 10, 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.*