# GS Mobile vs O

The clearest difference is update cadence: GS Mobile at every 2 months against O's every 11 months. GS Mobile also leads on device support (3 vs 1) and iOS requirement (9.1 vs 16.0). On price, 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.

GS Mobile ships an update every 2 months, O every 11 months. The most recent releases landed on September 27, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | GS Mobile | O |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/o-ring-master/id1072051820/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 11 months |
| Monetization | — | Free |
| Size | 13 MB | 47 MB |
| Requires iOS | **9.1** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [SystemSat](https://appshunter.io/developer/985734878) | [GE MAO RUBBER INDUSTRIAL CO., LTD.](https://appshunter.io/developer/1078558543) |

## What reviewers say

### GS Mobile

[App page](https://appshunter.io/ios/app/gs-mobile/id1018882195)

**Features:** macOS Compatibility

**In-app purchases:** none


### O

[App page](https://appshunter.io/ios/app/o-ring-master/id1072051820)

This app provides a comprehensive offline tool for selecting standard rubber seal sizes, including O-Rings, X-Rings, and Back-Up Rings. It offers dimension searches, housing calculations for various sealing applications, and supports multiple international standards in both metric and imperial units.

**Highlights:** Offline standard rubber seal size selection, Search for O-Ring, X-Ring, and Back-Up Ring sizes, O-Ring housing calculations for sealing applications, Supports multiple international standards (AS568, METRIC, JIS, etc.), Metric and Imperial unit support, Substitutable O-Ring size suggestions

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

**In-app purchases:** none


## Frequently asked questions

### Is GS Mobile free?

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

### Is O free?

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

### Do GS Mobile or O have ads?

Neither GS Mobile nor O shows ads.

### Which is updated more often, GS Mobile or O?

GS Mobile ships an update every 2 months, and O every 11 months. Most recently, GS Mobile was updated on September 27, 2026 and O on October 12, 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.*