# 环境哨兵 vs ESP

The clearest difference is in-app purchases: 环境哨兵 at none against ESP's 1. 环境哨兵 also leads on device support (3 vs 1) and iOS requirement (11.0 vs 16.0). On price and ads there is nothing between them.

Both are free to download. ESP sells 1 one-off in-app purchase. 环境哨兵 asks for nothing beyond the download.

## The numbers

| Metric | 环境哨兵 | ESP |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | — |
| Size | 23 MB | 1 MB |
| Requires iOS | **11.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Vispek Co., Ltd](https://appshunter.io/developer/1447793884) | [Wuhan FireFrog Technology Co., Ltd.](https://appshunter.io/developer/917083159) |

## What reviewers say

### 环境哨兵

[App page](https://appshunter.io/ios/app/id6445802438)

**Features:** macOS Compatibility

**In-app purchases:** none


### ESP

[App page](https://appshunter.io/ios/app/esp-airlink/id6756355176)

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| a cup of coffee | $0.99 | one-time |


## Frequently asked questions

### Is 环境哨兵 free?

环境哨兵 is free to download, with no in-app purchases.

### Is ESP free?

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

### Do 环境哨兵 or ESP have ads?

Neither 环境哨兵 nor ESP shows ads.

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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.*