# T vs J

The clearest difference is update cadence: T at every 3 weeks against J's every 3 months. J's advantage is iOS requirement (13.0 vs 15.0). On price, ads, 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.

T ships an update every 3 weeks, J every 3 months. The most recent releases landed on September 9, 2026 and September 17, 2026 respectively.

## The numbers

| Metric | T | J |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 3 months |
| Monetization | Free | — |
| Size | 216 MB | 81 MB |
| Requires iOS | 15.0 | **13.0** |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 4+ | 17+ |
| Developer | [iConsole](https://appshunter.io/developer/539376672) | [weichieh lin](https://appshunter.io/developer/1683777188) |

## What reviewers say

### T

[App page](https://appshunter.io/ios/app/t-sox/id1551591004)

This application connects to smart indoor bike trainers via FTMS protocols. It allows users to check trainer connection status, update firmware, and perform a spindown calibration to ensure accurate power readings for different bike setups.

**Highlights:** FTMS communication protocol support, BLE connection status check, Firmware version confirmation and update, Spindown function for power calibration, Redefine power output for training platforms

**Features:** macOS Compatibility

**In-app purchases:** none


### J

[App page](https://appshunter.io/ios/app/j-lin-infinity/id1643486063)

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

**In-app purchases:** none


## Frequently asked questions

### Is T free?

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

### Is J free?

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

### Do T or J have ads?

Neither T nor J shows ads.

### Which is updated more often, T or J?

T ships an update every 3 weeks, and J every 3 months. Most recently, T was updated on September 9, 2026 and J on September 17, 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.*