# Si vs Penlight.

The clearest difference is price: Si at Free against Penlight.'s $1.99. Si also leads on iOS requirement (9.1 vs 16.0). Penlight.'s advantage is update cadence (daily vs every 5 months). On ads, in-app purchases and device support there is nothing between them.

Si is free to download; Penlight. costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Si ships an update every 5 months, Penlight. daily. The most recent releases landed on September 8, 2026 and September 14, 2026 respectively.

## The numbers

| Metric | Si | Penlight. |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/penlight/id6621271103/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 5 months | **Daily** |
| Monetization | — | Paid |
| Size | 12 MB | 1 MB |
| Requires iOS | **9.1** | 16.0 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [旭日东方](https://appshunter.io/developer/1472957256) | [My Call Bag LLC](https://appshunter.io/developer/1243282862) |

## What reviewers say

### Si

[App page](https://appshunter.io/ios/app/si-link/id1484583420)

**Features:** macOS Compatibility

**In-app purchases:** none


### Penlight.

[App page](https://appshunter.io/ios/app/penlight/id6621271103)

This app provides a digital penlight with adjustable brightness and a built-in ruler for quick measurements. It also features color inversion for different examination needs and easy calibration using a credit card.

**Highlights:** Adjustable digital penlight brightness, Credit card calibration for accuracy, Color inversion for light/dark modes, Metric and imperial ruler, Educational examination tool

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

**In-app purchases:** none


## Frequently asked questions

### Is Si free?

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

### Is Penlight. free?

Penlight. costs $1.99, with no in-app purchases.

### Do Si or Penlight. have ads?

Neither Si nor Penlight. shows ads.

### Which is updated more often, Si or Penlight.?

Si ships an update every 5 months, and Penlight. daily. Most recently, Si was updated on September 8, 2026 and Penlight. on September 14, 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.*