# Self Defense Alarm Lite vs Visual Displacement Meter

The clearest difference is update cadence: Visual Displacement Meter at fortnightly against Self Defense Alarm Lite's every 10 months. Self Defense Alarm Lite's advantage is iOS requirement (8.0 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.

Self Defense Alarm Lite ships an update every 10 months, Visual Displacement Meter fortnightly. The most recent releases landed on October 26, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | Self Defense Alarm Lite | Visual Displacement Meter |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 10 months | **Fortnightly** |
| Size | 34 MB | 59 MB |
| Requires iOS | **8.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPod, Mac |
| Age rating | 4+ | 4+ |
| Developer | [CHIA HO KUO](https://appshunter.io/developer/433588685) | [Inteagle Information Technology(Dongguan) Co., Ltd.](https://appshunter.io/developer/1720865930) |

## What reviewers say

### Self Defense Alarm Lite

[App page](https://appshunter.io/ios/app/self-defense-alarm-lite/id851002131)

**Features:** macOS Compatibility

**In-app purchases:** none


### Visual Displacement Meter

[App page](https://appshunter.io/ios/app/visual-displacement-meter/id6749835043)

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Self Defense Alarm Lite free?

Self Defense Alarm Lite is free to download, with no in-app purchases.

### Is Visual Displacement Meter free?

Visual Displacement Meter is free to download, with no in-app purchases.

### Do Self Defense Alarm Lite or Visual Displacement Meter have ads?

Neither Self Defense Alarm Lite nor Visual Displacement Meter shows ads.

### Which is updated more often, Self Defense Alarm Lite or Visual Displacement Meter?

Self Defense Alarm Lite ships an update every 10 months, and Visual Displacement Meter fortnightly. Most recently, Self Defense Alarm Lite was updated on October 26, 2026 and Visual Displacement Meter on October 28, 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.*