# Automobile Engineering Book vs PDFReader Voice

The clearest difference is price: Automobile Engineering Book at Free against PDFReader Voice's $0.99. Automobile Engineering Book also leads on iOS requirement (14.0 vs 26.0). PDFReader Voice's advantage is in-app purchases (none vs 5) and update cadence (every 4 days vs every 5 weeks). On ads and device support there is nothing between them.

Automobile Engineering Book is free to download; PDFReader Voice costs $0.99 up front. Automobile Engineering Book sells 4 in-app purchases, starting at $2.99 per 3 months. PDFReader Voice asks for nothing beyond the download.

Automobile Engineering Book ships an update every 5 weeks, PDFReader Voice every 4 days. The most recent releases landed on October 16, 2026 and September 19, 2026 respectively.

## The numbers

| Metric | Automobile Engineering Book | PDFReader Voice |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| Rating | **[4.6 (9 ratings)](https://appshunter.io/ios/app/automobile-engineering-book/id1583758958/reviews)** | — |
| Number of ratings | **9** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 5 weeks | **Every 4 days** |
| Monetization | Free with in-app purchases | — |
| Size | 136 MB | 3 MB |
| Requires iOS | **14.0** | 26.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Oleksandr Pereshein](https://appshunter.io/developer/1041461209) | [MANJUR KOLHAR](https://appshunter.io/developer/1845533906) |

## What reviewers say

### Automobile Engineering Book

[App page](https://appshunter.io/ios/app/automobile-engineering-book/id1583758958)

This app provides a comprehensive yet accessible guide to automobile engineering. It covers basic vehicle structure, common malfunctions, and maintenance rules in a clear, engaging format with ample illustrations. Ideal for novice drivers and anyone seeking to understand their car better.

**Highlights:** Basic vehicle structure information, Common malfunctions and solutions, Operation and maintenance rules, Simple language explanations of car systems, Extensive illustrative material

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full version | $2.99 | per 3 months |
| Full version for three months | $2.99 | one-time |
| Full version for one year | $4.99 | one-time |
| Full version forever | $6.99 | one-time |


### PDFReader Voice

[App page](https://appshunter.io/ios/app/pdfreader-voice/id6754202484)

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

**In-app purchases:** none


## Frequently asked questions

### Is Automobile Engineering Book free?

Automobile Engineering Book is free to download, with in-app purchases available.

### Is PDFReader Voice free?

PDFReader Voice costs $0.99, with no in-app purchases.

### Do Automobile Engineering Book or PDFReader Voice have ads?

Neither Automobile Engineering Book nor PDFReader Voice shows ads.

### Which is updated more often, Automobile Engineering Book or PDFReader Voice?

Automobile Engineering Book ships an update every 5 weeks, and PDFReader Voice every 4 days. Most recently, Automobile Engineering Book was updated on October 16, 2026 and PDFReader Voice on September 19, 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.*