# RAD vs Sentinel

The clearest difference is in-app purchases: RAD at none against Sentinel's 2. RAD also leads on iOS requirement (11.0 vs 15.1). Sentinel's advantage is update cadence (every 9 days vs every 3 weeks). On price, ads and device support there is nothing between them.

Both are free to download. Sentinel sells 2 in-app purchases, starting at $29.99 per month. RAD asks for nothing beyond the download.

RAD ships an update every 3 weeks, Sentinel every 9 days. The most recent releases landed on September 9, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | RAD | Sentinel |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (2 ratings)](https://appshunter.io/ios/app/rad-lab/id1567412980/reviews)** | — |
| Number of ratings | **2** | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Every 9 days** |
| Monetization | Free | — |
| Size | 109 MB | 39 MB |
| Requires iOS | **11.0** | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [femto-TECH, INC.](https://appshunter.io/developer/1498460992) | [Eija Huttunen](https://appshunter.io/developer/1887793867) |

## What reviewers say

### RAD

[App page](https://appshunter.io/ios/app/rad-lab/id1567412980)

Connect to continuous radon monitoring devices to download and analyze radon data. Generate PDF reports directly from the app for easy sharing and record-keeping.

**Highlights:** Connect to femto-TECH CRM devices, Download radon monitoring data, Analyze collected data, Generate PDF reports, Data export functionality

**In-app purchases:** none


### Sentinel

[App page](https://appshunter.io/ios/app/sentinel-field-intelligence/id6761101801)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Sentinel Solo | $29.99 | per month |
| Sentinel Pro | $79.99 | per month |


## Frequently asked questions

### Is RAD free?

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

### Is Sentinel free?

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

### Do RAD or Sentinel have ads?

Neither RAD nor Sentinel shows ads.

### Which is updated more often, RAD or Sentinel?

RAD ships an update every 3 weeks, and Sentinel every 9 days. Most recently, RAD was updated on September 9, 2026 and Sentinel on September 10, 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.*