# O vs Smart Lock

The clearest difference is rating: O at 5.0 against Smart Lock's 1.0. Smart Lock's advantage is update cadence (every 2 months vs every 11 months) and iOS requirement (13.0 vs 16.0). 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.

O holds the better App Store score, 5.0 against 1.0. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

O ships an update every 11 months, Smart Lock every 2 months. The most recent releases landed on September 22, 2026 and June 11, 2026 respectively.

## The numbers

| Metric | O | Smart Lock |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/o-ring-master/id1072051820/reviews)** | [1.0 (1 ratings)](https://appshunter.io/ios/app/smart-lock-one-key-access/id1136587698/reviews) |
| Number of ratings | 1 | 1 |
| Positive 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 | 9 MB |
| Requires iOS | 16.0 | **13.0** |
| Devices | iPhone | **iPhone, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [GE MAO RUBBER INDUSTRIAL CO., LTD.](https://appshunter.io/developer/1078558543) | [Hizima Technologies Co., Ltd](https://appshunter.io/developer/1680084643) |

## 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


### Smart Lock

[App page](https://appshunter.io/ios/app/smart-lock-one-key-access/id1136587698)

This utility app works with a specific mechatronic lock and key system to manage access and track operations. It allows users to find smart keys, open authorized locks, apply for access tickets, and view operation logs. The app also facilitates lock management and provides navigation to stations.

**Highlights:** Search and connect to Smart Keys, Open authorized Smart Locks, Apply for and manage lock access tickets, View daily, weekly, and monthly operation logs, Manage lock authorizations and One Time Passwords, Initialize, reset, and bind locks, Navigate to station locations

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is O free?

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

### Is Smart Lock free?

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

### Which has better reviews, O or Smart Lock?

O is rated higher. O averages 5.0 out of 5 from 1 ratings, while Smart Lock averages 1.0 from 1 ratings.

### Do O or Smart Lock have ads?

Neither O nor Smart Lock shows ads.

### Which is updated more often, O or Smart Lock?

O ships an update every 11 months, and Smart Lock every 2 months. Most recently, O was updated on September 22, 2026 and Smart Lock on June 11, 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.*