# PJFFfree vs TrackDays

The clearest difference is ads: TrackDays at none against PJFFfree's shown. PJFFfree's advantage is update cadence (every 5 weeks vs every 4 months) and iOS requirement (15.0 vs 17.0). On price, in-app purchases and device support there is nothing between them.

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

PJFFfree ships an update every 5 weeks, TrackDays every 4 months. The most recent releases landed on October 8, 2026 and September 29, 2026 respectively.

## The numbers

| Metric | PJFFfree | TrackDays |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/pjfffree/id629958775/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | **Every 5 weeks** | Every 4 months |
| Monetization | Ad-supported | — |
| Size | 7 MB | 2 MB |
| Requires iOS | **15.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [sigeyosi kanenishi](https://appshunter.io/developer/629958778) | [SAI AUNG MON](https://appshunter.io/developer/6775471645) |

## What reviewers say

### PJFFfree

[App page](https://appshunter.io/ios/app/pjfffree/id629958775)

This app serves as a manual for piping parts, focusing on Japanese specifications. It lists commonly used items based on manufacturer data and public dimension tables, with all measurements in millimeters.

**Highlights:** Piping parts manual, Japanese specifications, Commonly used parts listing, Manufacturer data integration, Millimeter measurements, JIS standards compliance

**Features:** macOS Compatibility

**In-app purchases:** none


### TrackDays

[App page](https://appshunter.io/ios/app/trackdays/id6775471643)

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

**In-app purchases:** none


## Frequently asked questions

### Is PJFFfree free?

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

### Is TrackDays free?

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

### Do PJFFfree or TrackDays have ads?

PJFFfree shows ads; TrackDays does not.

### Which is updated more often, PJFFfree or TrackDays?

PJFFfree ships an update every 5 weeks, and TrackDays every 4 months. Most recently, PJFFfree was updated on October 8, 2026 and TrackDays on September 29, 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.*