# BK400 vs Polying 2

The clearest difference is update cadence: BK400 at weekly against Polying 2's every 3 weeks. 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, Polying 2 every 3 weeks. The most recent releases landed on September 24, 2026 and September 15, 2026 respectively.

## The numbers

| Metric | BK400 | Polying 2 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Weekly** | Every 3 weeks |
| Size | 21 MB | 1 MB |
| Requires iOS | **15.0** | 16.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [祖策 谢](https://appshunter.io/developer/983519195) | [深圳艾斯特创新科技有限公司](https://appshunter.io/developer/1405370693) |

## What reviewers say

### BK400

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

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

**In-app purchases:** none


### Polying 2

[App page](https://appshunter.io/ios/app/polying-2/id6762327888)

**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 Polying 2 free?

Polying 2 is free to download, with no in-app purchases.

### Do BK400 or Polying 2 have ads?

Neither BK400 nor Polying 2 shows ads.

### Which is updated more often, BK400 or Polying 2?

BK400 ships an update weekly, and Polying 2 every 3 weeks. Most recently, BK400 was updated on September 24, 2026 and Polying 2 on September 15, 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.*