# Hydro CM vs Rolls

The clearest difference is rating: Rolls at 5.0 against Hydro CM's 4.0. Hydro CM's advantage is update cadence (every 4 days vs every 3 months) and iOS requirement (12.0 vs 18.0). On price, ratings volume, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Rolls holds the better App Store score, 5.0 against 4.0. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

Hydro CM ships an update every 4 days, Rolls every 3 months. The most recent releases landed on July 7, 2026 and June 1, 2026 respectively.

## The numbers

| Metric | Hydro CM | Rolls |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.0 (1 ratings)](https://appshunter.io/ios/app/hydro-cm/id1132190359/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/rolls-royce-code-of-conduct/id1297979821/reviews)** |
| Number of ratings | 1 | 1 |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 4 days** | Every 3 months |
| Monetization | Free | Free |
| Size | 361 MB | 89 MB |
| Requires iOS | **12.0** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Bloc Digital](https://appshunter.io/developer/873078731) | [Rolls-Royce Holdings Plc](https://appshunter.io/developer/501951395) |

## What reviewers say

### Hydro CM

[App page](https://appshunter.io/ios/app/hydro-cm/id1132190359)

Explore a 3D augmented reality model of a hydro turbine to understand condition-monitoring solutions. Visualize optimized sensor installations and discover hardware/software that translates data into maintenance actions, protecting your assets and reducing costs.

**Highlights:** Augmented reality turbine visualization, Optimized sensor installation display, Maintenance action insights, Asset protection and optimization, Cost reduction analysis

**Features:** macOS Compatibility

**In-app purchases:** none


### Rolls

[App page](https://appshunter.io/ios/app/rolls-royce-code-of-conduct/id1297979821)

This app provides employees and stakeholders with the company's principles on key activities and core Group Policies. It details standards of conduct, a decision-making framework for dilemmas, and channels for raising concerns. Interactive exercises help users navigate ethical issues.

**Highlights:** Company principles and Group Policies, Standards of conduct, Decision-making framework (TRUST model), Speak up channels for concerns, Interactive ethical dilemma exercises, Information for employees, customers, suppliers, and investors

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Hydro CM free?

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

### Is Rolls free?

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

### Which has better reviews, Hydro CM or Rolls?

Rolls is rated higher. Hydro CM averages 4.0 out of 5 from 1 ratings, while Rolls averages 5.0 from 1 ratings.

### Do Hydro CM or Rolls have ads?

Neither Hydro CM nor Rolls shows ads.

### Which is updated more often, Hydro CM or Rolls?

Hydro CM ships an update every 4 days, and Rolls every 3 months. Most recently, Hydro CM was updated on July 7, 2026 and Rolls on June 1, 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.*