# Mars Book vs ぐるぐる ZEISS IX型

The clearest difference is iOS requirement: Mars Book at 9.0 against ぐるぐる ZEISS IX型's 12.0. On price, update cadence, ads and in-app purchases there is nothing between them.

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

Mars Book ships an update every 13 months, ぐるぐる ZEISS IX型 every 17 months. The most recent releases landed on October 26, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | Mars Book | ぐるぐる ZEISS IX型 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 13 months** | Every 17 months |
| Size | 14 MB | 206 MB |
| Requires iOS | **9.0** | 12.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Vixen Co.,Ltd.](https://appshunter.io/developer/536188843) | [IMAGE FACTORY CO., LTD.](https://appshunter.io/developer/882653089) |

## What reviewers say

### Mars Book

[App page](https://appshunter.io/ios/app/mars-book/id1342509724)

**In-app purchases:** none


### ぐるぐる ZEISS IX型

[App page](https://appshunter.io/ios/app/zeiss-ix/id6450916756)

**In-app purchases:** none


## Frequently asked questions

### Is Mars Book free?

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

### Is ぐるぐる ZEISS IX型 free?

ぐるぐる ZEISS IX型 is free to download, with no in-app purchases.

### Do Mars Book or ぐるぐる ZEISS IX型 have ads?

Neither Mars Book nor ぐるぐる ZEISS IX型 shows ads.

### Which is updated more often, Mars Book or ぐるぐる ZEISS IX型?

Mars Book ships an update every 13 months, and ぐるぐる ZEISS IX型 every 17 months. Most recently, Mars Book was updated on October 26, 2026 and ぐるぐる ZEISS IX型 on November 3, 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.*