# EM3720 vs E Sentry Systems

The clearest difference is update cadence: E Sentry Systems at every 3 weeks against EM3720's every 4 months. EM3720's advantage is iOS requirement (11.0 vs 16.0). 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.

EM3720 ships an update every 4 months, E Sentry Systems every 3 weeks. The most recent releases landed on November 2, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | EM3720 | E Sentry Systems |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 3 weeks** |
| Size | 6 MB | 54 MB |
| Requires iOS | **11.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [ZHANGZHOU EASTERN INTELLIGENT METER CO., LTD.](https://appshunter.io/developer/1064839954) | [IRISS Inc](https://appshunter.io/developer/1245323320) |

## What reviewers say

### EM3720

[App page](https://appshunter.io/ios/app/em3720/id1376380656)

**Features:** macOS Compatibility

**In-app purchases:** none


### E Sentry Systems

[App page](https://appshunter.io/ios/app/e-sentry-systems/id6444192723)

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

**In-app purchases:** none


## Frequently asked questions

### Is EM3720 free?

EM3720 is free to download, with no in-app purchases.

### Is E Sentry Systems free?

E Sentry Systems is free to download, with no in-app purchases.

### Do EM3720 or E Sentry Systems have ads?

Neither EM3720 nor E Sentry Systems shows ads.

### Which is updated more often, EM3720 or E Sentry Systems?

EM3720 ships an update every 4 months, and E Sentry Systems every 3 weeks. Most recently, EM3720 was updated on November 2, 2026 and E Sentry Systems on November 3, 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.*