# Volkano Ring vs STF ZEN

Volkano Ring and STF ZEN are too close to call on the numbers: across 5 compared parameters — price, ads, in-app purchases and device support among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

## The numbers

| Metric | Volkano Ring | STF ZEN |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 23 months | — |
| Size | 125 MB | 45 MB |
| Requires iOS | 9 | 9.0 |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [SMD Technologies Pty LTD](https://appshunter.io/developer/1455444362) | [STUFFACTORY](https://appshunter.io/developer/1476804950) |

## What reviewers say

### Volkano Ring

[App page](https://appshunter.io/ios/app/volkano-ring/id6478380793)

**Features:** macOS Compatibility

**In-app purchases:** none


### STF ZEN

[App page](https://appshunter.io/ios/app/stf-zen/id6730119787)

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

**In-app purchases:** none


## Frequently asked questions

### Is Volkano Ring free?

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

### Is STF ZEN free?

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

### Do Volkano Ring or STF ZEN have ads?

Neither Volkano Ring nor STF ZEN shows ads.

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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.*