# 钥匙尺子 vs MTRay

The clearest difference is in-app purchases: 钥匙尺子 at none against MTRay's 1. 钥匙尺子 also leads on iOS requirement (10.0 vs 17.0). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. MTRay sells 1 one-off in-app purchase. 钥匙尺子 asks for nothing beyond the download.

钥匙尺子 ships an update fortnightly, MTRay every 8 days. The most recent releases landed on October 25, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | 钥匙尺子 | MTRay |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Fortnightly | **Every 8 days** |
| Size | 31 MB | 63 MB |
| Requires iOS | **10.0** | 17.0 |
| Devices | iPhone, iPod | **iPhone, iPad, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Wuxi Kaiyang Electronic Technology Co., Ltd.](https://appshunter.io/developer/1131154502) | [Chill Information Technology Limited](https://appshunter.io/developer/1536753936) |

## What reviewers say

### 钥匙尺子

[App page](https://appshunter.io/ios/app/id1479796469)

**Features:** macOS Compatibility

**In-app purchases:** none


### MTRay

[App page](https://appshunter.io/ios/app/mtray/id6761518102)

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| MTRay Pro | $7.99 | one-time |


## Frequently asked questions

### Is 钥匙尺子 free?

钥匙尺子 is free to download, with no in-app purchases.

### Is MTRay free?

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

### Do 钥匙尺子 or MTRay have ads?

Neither 钥匙尺子 nor MTRay shows ads.

### Which is updated more often, 钥匙尺子 or MTRay?

钥匙尺子 ships an update fortnightly, and MTRay every 8 days. Most recently, 钥匙尺子 was updated on October 25, 2026 and MTRay on October 31, 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.*