# BK400 vs X

The clearest difference is update cadence: X at daily against BK400's weekly. X also leads on iOS requirement (13.0 vs 15.0). On price, ads, 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.

BK400 ships an update weekly, X daily. The most recent releases landed on October 25, 2026 and October 14, 2026 respectively.

## The numbers

| Metric | BK400 | X |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Weekly | **Daily** |
| Size | 21 MB | 66 MB |
| Requires iOS | 15.0 | **13.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [祖策 谢](https://appshunter.io/developer/983519195) | [Revogi Innovation Co., Ltd.](https://appshunter.io/developer/660013953) |

## What reviewers say

### BK400

[App page](https://appshunter.io/ios/app/bk400/id6760681499)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### X

[App page](https://appshunter.io/ios/app/x-sense/id6808180594)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is BK400 free?

BK400 is free to download, with no in-app purchases.

### Is X free?

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

### Do BK400 or X have ads?

Neither BK400 nor X shows ads.

### Which is updated more often, BK400 or X?

BK400 ships an update weekly, and X daily. Most recently, BK400 was updated on October 25, 2026 and X on October 14, 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.*