# O vs EWINBOX

The clearest difference is review sentiment: O at 100% against EWINBOX's 0%. EWINBOX's advantage is update cadence (every 2 months vs every 11 months) and iOS requirement (12.0 vs 16.0). On price, ads, in-app purchases and monetization model there is nothing between them.

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

O ships an update every 11 months, EWINBOX every 2 months. The most recent releases landed on September 26, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | O | EWINBOX |
| --- | --- | --- |
| 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** | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 11 months | **Every 2 months** |
| Monetization | Free | Free |
| Size | 47 MB | 223 MB |
| Requires iOS | 16.0 | **12.0** |
| Devices | iPhone | **iPhone, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [GE MAO RUBBER INDUSTRIAL CO., LTD.](https://appshunter.io/developer/1078558543) | [BOE Yiyun Technology Co., Ltd.](https://appshunter.io/developer/1267195265) |

## What reviewers say

### 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


### EWINBOX

[App page](https://appshunter.io/ios/app/ewinbox/id6505099399)

This utility allows you to personalize your phone case by displaying custom photos or text on its ink screen. Utilize your phone's NFC to transfer designs for a long-lasting, unique look. The app offers a variety of materials and theme options for DIY creation.

**Highlights:** Customizable ink screen display, NFC photo and text transfer, Personalized DIY themes, Large library of design materials, Regular theme content updates

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

**In-app purchases:** none


## Frequently asked questions

### Is O free?

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

### Is EWINBOX free?

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

### Do O or EWINBOX have ads?

Neither O nor EWINBOX shows ads.

### Which is updated more often, O or EWINBOX?

O ships an update every 11 months, and EWINBOX every 2 months. Most recently, O was updated on September 26, 2026 and EWINBOX on October 10, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*