# Calibration Keeper vs S4C

The clearest difference is device support: Calibration Keeper at 3 against S4C's —. S4C's advantage is iOS requirement (11.0 vs 15.1). On price 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.

## The numbers

| Metric | Calibration Keeper | S4C |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | — |
| Update frequency | Every 16 months | — |
| Size | 22 MB | 35 MB |
| Requires iOS | 15.1 | **11.0** |
| Devices | **iPhone, iPad, iPod** | — |
| Age rating | 4+ | 17+ |
| Developer | [Trihydro Corporation](https://appshunter.io/developer/920601995) | [SUTO iTEC (China) Co. Ltd](https://appshunter.io/developer/1511502112) |

## What reviewers say

### Calibration Keeper

[App page](https://appshunter.io/ios/app/calibration-keeper/id1465790622)

**Features:** macOS Compatibility

**In-app purchases:** none


### S4C

[App page](https://appshunter.io/ios/app/s4c-dp/id1641425429)

**In-app purchases:** none


## Frequently asked questions

### Is Calibration Keeper free?

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

### Is S4C free?

S4C is free to download, with no in-app purchases.

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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.*