# O vs Weight Log

The clearest difference is in-app purchases: O at none against Weight Log's 7. Weight Log's advantage is update cadence (weekly vs every 11 months) and iOS requirement (14.0 vs 16.0). On price, ads and device support there is nothing between them.

Both are free to download. Weight Log sells 7 in-app purchases, starting at $2.99 per month. O asks for nothing beyond the download.

O ships an update every 11 months, Weight Log weekly. The most recent releases landed on September 26, 2026 and September 22, 2026 respectively.

## The numbers

| Metric | O | Weight Log |
| --- | --- | --- |
| 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** | Yes |
| Ads | No | No |
| Update frequency | Every 11 months | **Weekly** |
| Monetization | Free | — |
| Size | 47 MB | 126 MB |
| Requires iOS | 16.0 | **14.0** |
| Devices | iPhone | **iPhone, iPod** |
| Age rating | 4+ | 17+ |
| Developer | [GE MAO RUBBER INDUSTRIAL CO., LTD.](https://appshunter.io/developer/1078558543) | [迪 王](https://appshunter.io/developer/1598269381) |

## 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


### Weight Log

[App page](https://appshunter.io/ios/app/weight-log-track-progress/id6758137970)

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

**In-app purchases (7)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 包月会员 | $2.99 | per month |
| 年度会员 | $3.99 | per year |
| Monthly Membership | $3.99 | per month |
| 季度会员 | $4.99 | per 3 months |
| Quarterly Membership | $7.99 | per 3 months |
| 年度会员 | $9.99 | per year |
| Annual Membership | $11.99 | per year |


## Frequently asked questions

### Is O free?

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

### Is Weight Log free?

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

### Do O or Weight Log have ads?

Neither O nor Weight Log shows ads.

### Which is updated more often, O or Weight Log?

O ships an update every 11 months, and Weight Log weekly. Most recently, O was updated on September 26, 2026 and Weight Log on September 22, 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.*