# MT Refinish vs CO2 on Watch & Lockscreen

The clearest difference is in-app purchases: MT Refinish at none against CO2 on Watch & Lockscreen's 8. MT Refinish also leads on iOS requirement (11.0 vs 17.6). CO2 on Watch & Lockscreen's advantage is update cadence (weekly vs every 4 months). On price, ads and device support there is nothing between them.

Both are free to download. CO2 on Watch & Lockscreen sells 8 in-app purchases, starting at $3.99 per month. MT Refinish asks for nothing beyond the download.

MT Refinish ships an update every 4 months, CO2 on Watch & Lockscreen weekly. The most recent releases landed on November 7, 2026 and November 4, 2026 respectively.

## The numbers

| Metric | MT Refinish | CO2 on Watch & Lockscreen |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[1.0 (2 ratings)](https://appshunter.io/ios/app/co2-on-watch-and-lockscreen/id6738605498/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | — | 50.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Weekly** |
| Monetization | — | Free with in-app purchases |
| Size | 16 MB | 28 MB |
| Requires iOS | **11.0** | 17.6 |
| Devices | iPhone, iPod | **iPhone, iPad, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [METTLER-TOLEDO TECHNOLOGIES CHINA CO., LTD.](https://appshunter.io/developer/1724697684) | [Kevin Floch](https://appshunter.io/developer/1772752224) |

## What reviewers say

### MT Refinish

[App page](https://appshunter.io/ios/app/mt-refinish/id1614352896)

**Features:** macOS Compatibility

**In-app purchases:** none


### CO2 on Watch & Lockscreen

[App page](https://appshunter.io/ios/app/co2-on-watch-and-lockscreen/id6738605498)

Monitor CO2 levels from compatible devices directly on your Apple Watch and iPhone Lock Screen. Receive smart alerts and view real-time air quality data with color-coded visuals for quick understanding.

**Highlights:** Apple Watch complications with history graph, iPhone Lock Screen widgets, Customizable CO2 threshold alerts, Background monitoring, Live Activity for real-time data, Color-coded air quality visuals

**Features:** macOS Compatibility

**In-app purchases (8)**

| Purchase | Price | Billing |
| --- | --- | --- |
| CO2_Monthly | $3.99 | per month |
| CO2_Annually | $29.99 | per year |
| Small tip | $4.99 | one-time |
| Medium tip | $9.99 | one-time |
| Large tip | $19.99 | one-time |
| CO2_Lifetime_Upgrade2 | $24.99 | one-time |
| CO2_Lifetime | $49.99 | one-time |
| Extra large tip | $49.99 | one-time |


## Frequently asked questions

### Is MT Refinish free?

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

### Is CO2 on Watch & Lockscreen free?

CO2 on Watch & Lockscreen is free to download, with in-app purchases available.

### Do MT Refinish or CO2 on Watch & Lockscreen have ads?

Neither MT Refinish nor CO2 on Watch & Lockscreen shows ads.

### Which is updated more often, MT Refinish or CO2 on Watch & Lockscreen?

MT Refinish ships an update every 4 months, and CO2 on Watch & Lockscreen weekly. Most recently, MT Refinish was updated on November 7, 2026 and CO2 on Watch & Lockscreen on November 4, 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.*