# OKN Drum vs 528i

The clearest difference is rating: 528i at 5.0 against OKN Drum's 4.1. 528i also leads on in-app purchases (none vs 1) and iOS requirement (14.0.0 vs 17.0). OKN Drum's advantage is ratings volume (16 vs 3). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. OKN Drum sells 1 one-off in-app purchase. 528i asks for nothing beyond the download.

528i holds the better App Store score, 5.0 against 4.1. That said, the two scores are not equally well evidenced: OKN Drum has 16 ratings behind it against 3, so its average is the more settled of the two.

OKN Drum ships an update every 2 weeks, 528i fortnightly. The most recent releases landed on October 30, 2026 and October 16, 2026 respectively.

## The numbers

| Metric | OKN Drum | 528i |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.1 (16 ratings)](https://appshunter.io/ios/app/okn-drum-optokinetic/id6474153180/reviews) | **[5.0 (3 ratings)](https://appshunter.io/ios/app/528i/id6738430099/reviews)** |
| Number of ratings | **16** | 3 |
| Positive reviews | 46.2% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 2 weeks | **Fortnightly** |
| Monetization | Paid | **Free** |
| Size | 14 MB | 35 MB |
| Requires iOS | 17.0 | **14.0.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 17+ |
| Developer | [My Call Bag LLC](https://appshunter.io/developer/1243282862) | [528 INNOVATIONS LLC](https://appshunter.io/developer/1780816602) |

## What reviewers say

### OKN Drum

[App page](https://appshunter.io/ios/app/okn-drum-optokinetic/id6474153180)

This app offers a digital optokinetic drum for vision testing and exercises. Customize stripe width, speed, and color, with options for pediatric targets. It also features a metronome and camera recording for eye movements.

**Highlights:** Adjustable stripe width and speed, Selectable black or red stripes, Pediatric targets (puppies, dinosaurs, animals), Full-screen mode, Integrated metronome, Record eye movements with camera, Upload custom images for drum

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Lifetime Access | $4.99 | one-time |


### 528i

[App page](https://appshunter.io/ios/app/528i/id6738430099)

This app guides users through laser therapy sessions with step-by-step instructions and instructional videos. It connects to a laser device to optimize timing, frequency, and application for photobiomodulation and low-level laser therapy.

**Highlights:** Step-by-step smart guidance, Interactive instructional videos, Wavelength recommendations, Device connectivity, Precision wellness at home

**In-app purchases:** none


## Frequently asked questions

### Is OKN Drum free?

OKN Drum is free to download, with in-app purchases available.

### Is 528i free?

528i is free to download, with no in-app purchases.

### Which has better reviews, OKN Drum or 528i?

528i is rated higher. OKN Drum averages 4.1 out of 5 from 16 ratings, while 528i averages 5.0 from 3 ratings.

### Do OKN Drum or 528i have ads?

Neither OKN Drum nor 528i shows ads.

### Which is updated more often, OKN Drum or 528i?

OKN Drum ships an update every 2 weeks, and 528i fortnightly. Most recently, OKN Drum was updated on October 30, 2026 and 528i on October 16, 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.*