# Gear Design vs Nitrox by Envivia

The clearest difference is review sentiment: Nitrox by Envivia at 100% against Gear Design's 0%. Nitrox by Envivia also leads on price (Free vs $2.99) and rating (5.0 vs 1.5). Gear Design's advantage is in-app purchases (none vs 4) and iOS requirement (9.3 vs 15.6). On ratings volume and ads there is nothing between them.

Nitrox by Envivia is free to download; Gear Design costs $2.99 up front. Nitrox by Envivia sells 4 in-app purchases, starting at $9.99 per year. Gear Design asks for nothing beyond the download.

Nitrox by Envivia holds the better App Store score, 5.0 against 1.5. Both are backed by a comparable volume of ratings — 2 and 1 respectively. Written reviews point the same way: 0% of Gear Design's written reviews are positive against 100% of Nitrox by Envivia's.

Gear Design ships an update every 12 months, Nitrox by Envivia every 6 weeks. The most recent releases landed on October 9, 2026 and October 23, 2026 respectively.

## The numbers

| Metric | Gear Design | Nitrox by Envivia |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | [1.5 (2 ratings)](https://appshunter.io/ios/app/gear-design/id1136191442/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/nitrox-by-envivia/id1613770132/reviews)** |
| Number of ratings | **2** | 1 |
| Positive reviews | 0.0% of reviews | **100.0% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 12 months | **Every 6 weeks** |
| Monetization | Paid | **Free with in-app purchases** |
| Size | 38 MB | 72 MB |
| Requires iOS | **9.3** | 15.6 |
| Devices | iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 12+ |
| Developer | [DRH YAZILIM VE MUHENDISLIK HIZMETLERI LTD STI](https://appshunter.io/developer/914295588) | [ENVIVIA](https://appshunter.io/developer/1583628615) |

## What reviewers say

### Gear Design

[App page](https://appshunter.io/ios/app/gear-design/id1136191442)

Design involute gears with a CAD interface, allowing visual assessment through touch gestures. Generate and export STL data for 3D printing and perform tooth bending strength analysis with PDF sharing.

**Highlights:** Involute gear design, CAD interface, Touch gesture controls (zoom, rotate), STL data generation, Email export, Tooth bending strength analysis, PDF sharing

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

**In-app purchases:** none


### Nitrox by Envivia

[App page](https://appshunter.io/ios/app/nitrox-by-envivia/id1613770132)

This app is a premium digital guide for Nitrox diving, offering educational content and calculation tools to optimize dives. It helps divers understand oxygen limits, plan dives using gradient factors, and prepare for certification.

**Highlights:** Calculate MOD (Maximum Operating Depth), Manage oxygen partial pressure (PPO₂), Optimize Nitrox dive planning, Understand oxygen-related physiological limits, Prepare for Nitrox certification, Multilingual support

**Features:** Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium | $9.99 | per year |
| Thank you | $1.99 | one-time |
| Popular | $9.99 | one-time |
| Generous | $49.99 | one-time |


## Frequently asked questions

### Is Gear Design free?

Gear Design costs $2.99, with no in-app purchases.

### Is Nitrox by Envivia free?

Nitrox by Envivia is free to download, with in-app purchases available.

### Which has better reviews, Gear Design or Nitrox by Envivia?

Nitrox by Envivia is rated higher. Gear Design averages 1.5 out of 5 from 2 ratings, while Nitrox by Envivia averages 5.0 from 1 ratings.

### Do Gear Design or Nitrox by Envivia have ads?

Neither Gear Design nor Nitrox by Envivia shows ads.

### Which is updated more often, Gear Design or Nitrox by Envivia?

Gear Design ships an update every 12 months, and Nitrox by Envivia every 6 weeks. Most recently, Gear Design was updated on October 9, 2026 and Nitrox by Envivia on October 23, 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.*