# Cyl Duration vs ABG Expert

The clearest difference is review sentiment: ABG Expert at 100% against Cyl Duration's 42%. ABG Expert also leads on update cadence (every 5 months vs every 49 months) and rating (4.8 vs 4.5). Cyl Duration's advantage is iOS requirement (10.0 vs 13.0). 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.

ABG Expert holds the better App Store score, 4.8 against 4.5. Both are backed by a comparable volume of ratings — 8 and 9 respectively. Written reviews point the same way: 42% of Cyl Duration's written reviews are positive against 100% of ABG Expert's.

Cyl Duration ships an update every 49 months, ABG Expert every 5 months. The most recent releases landed on October 11, 2026 and October 3, 2026 respectively.

## The numbers

| Metric | Cyl Duration | ABG Expert |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.5 (8 ratings)](https://appshunter.io/ios/app/cyl-duration/id447311122/reviews) | **[4.8 (9 ratings)](https://appshunter.io/ios/app/abg-expert/id885575488/reviews)** |
| Number of ratings | 8 | **9** |
| Positive reviews | 41.7% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 49 months | **Every 5 months** |
| Monetization | Free | Free |
| Size | 17 MB | 2 MB |
| Requires iOS | **10.0** | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 12+ | 12+ |
| Developer | [Responsive Respiratory, Inc.](https://appshunter.io/developer/447311125) | [Brian Dale Vander Werf MD Inc](https://appshunter.io/developer/1521935908) |

## What reviewers say

### Cyl Duration

[App page](https://appshunter.io/ios/app/cyl-duration/id447311122)

Calculates remaining oxygen in a cylinder for ambulatory users. Input device, liter flow, and cylinder size for precise remaining hours and minutes. Provides peace of mind for oxygen users on the go.

**Highlights:** Calculate remaining oxygen hours/minutes, Input device settings, Input liter flow, Input cylinder size, Precise readout

**Features:** macOS Compatibility

**In-app purchases:** none


### ABG Expert

[App page](https://appshunter.io/ios/app/abg-expert/id885575488)

This medical tool provides accurate and flexible acid-base analysis for healthcare professionals. It offers detailed explanations, customizable ranges, and advanced features like anion gap correction and A-a gradient adjustments for various patient conditions and locations.

**Highlights:** Validated accuracy with real-world testing, Plausibility checks for physiologically impossible data, Automatic anion gap correction with albumin, Detailed explanations with equations, Separate or combined analysis of ABG, anion gap, A-a gradient, Customizable normal ranges for anion gap and delta gap, Age and barometric pressure adjustments for A-a gradient, Support for SI and non-SI units, Color-coded results and differential diagnoses, Adjustments for chronic respiratory conditions

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Cyl Duration free?

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

### Is ABG Expert free?

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

### Which has better reviews, Cyl Duration or ABG Expert?

ABG Expert is rated higher. Cyl Duration averages 4.5 out of 5 from 8 ratings, while ABG Expert averages 4.8 from 9 ratings.

### Do Cyl Duration or ABG Expert have ads?

Neither Cyl Duration nor ABG Expert shows ads.

### Which is updated more often, Cyl Duration or ABG Expert?

Cyl Duration ships an update every 49 months, and ABG Expert every 5 months. Most recently, Cyl Duration was updated on October 11, 2026 and ABG Expert on October 3, 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.*