# OsteoGauge vs E Sentry Systems

The clearest difference is price: E Sentry Systems at Free against OsteoGauge's $2.99. OsteoGauge's advantage is update cadence (daily vs every 3 weeks) and iOS requirement (10.0 vs 16.0). On ads, in-app purchases and device support there is nothing between them.

E Sentry Systems is free to download; OsteoGauge costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

OsteoGauge ships an update daily, E Sentry Systems every 3 weeks. The most recent releases landed on September 14, 2026 and September 9, 2026 respectively.

## The numbers

| Metric | OsteoGauge | E Sentry Systems |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Daily** | Every 3 weeks |
| Size | 112 MB | 54 MB |
| Requires iOS | **10.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | +4 | 4+ |
| Developer | [Chu An Luo](https://appshunter.io/developer/1257642394) | [IRISS Inc,](https://appshunter.io/developer/1245323320) |

## What reviewers say

### OsteoGauge

[App page](https://appshunter.io/ios/app/osteogauge-lower-limb/id1312951940)

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

**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 OsteoGauge free?

OsteoGauge costs $2.99, with no in-app purchases.

### Is E Sentry Systems free?

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

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

Neither OsteoGauge nor E Sentry Systems shows ads.

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

OsteoGauge ships an update daily, and E Sentry Systems every 3 weeks. Most recently, OsteoGauge was updated on September 14, 2026 and E Sentry Systems on September 9, 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.*