# PDF Reader vs 有氧區間

The clearest difference is ads: 有氧區間 at none against PDF Reader's shown. 有氧區間 also leads on update cadence (every 9 days vs every 112 months). PDF Reader's advantage is iOS requirement (14.0 vs 18.6). On price, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

PDF Reader ships an update every 112 months, 有氧區間 every 9 days. The most recent releases landed on October 10, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | PDF Reader | 有氧區間 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 112 months | **Every 9 days** |
| Size | 10 MB | 16 MB |
| Requires iOS | **14.0** | 18.6 |
| Devices | iPhone, iPad, iPod | **iPhone, iPad, Mac, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [Aishvarya Sadasivam](https://appshunter.io/developer/1062048241) | [GilesWang](https://appshunter.io/developer/524054173) |

## What reviewers say

### PDF Reader

[App page](https://appshunter.io/ios/app/pdf-reader-simple/id1084659776)

**Features:** macOS Compatibility

**In-app purchases:** none


### 有氧區間

[App page](https://appshunter.io/ios/app/id6769687075)

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

**In-app purchases:** none


## Frequently asked questions

### Is PDF Reader free?

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

### Is 有氧區間 free?

有氧區間 is free to download, with no in-app purchases.

### Do PDF Reader or 有氧區間 have ads?

PDF Reader shows ads; 有氧區間 does not.

### Which is updated more often, PDF Reader or 有氧區間?

PDF Reader ships an update every 112 months, and 有氧區間 every 9 days. Most recently, PDF Reader was updated on October 10, 2026 and 有氧區間 on October 6, 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.*