# 3Sigma mobile CRM vs Pen Book

The clearest difference is iOS requirement: 3Sigma mobile CRM at 15.1 against Pen Book's 26.1. On price, update cadence, ads and in-app purchases there is nothing between them.

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

3Sigma mobile CRM ships an update every 8 days, Pen Book weekly. Both last shipped on October 24, 2026.

## The numbers

| Metric | 3Sigma mobile CRM | Pen Book |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 8 days | **Weekly** |
| Size | 76 MB | 8 MB |
| Requires iOS | **15.1** | 26.1 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 17+ | 4+ |
| Developer | [Vivek Rana](https://appshunter.io/developer/1704125607) | [Jovaris](https://appshunter.io/developer/6793435506) |

## What reviewers say

### 3Sigma mobile CRM

[App page](https://appshunter.io/ios/app/3sigma-mobile-crm/id6463200219)

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

**In-app purchases:** none


### Pen Book

[App page](https://appshunter.io/ios/app/pen-book/id6793435504)

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

**In-app purchases:** none


## Frequently asked questions

### Is 3Sigma mobile CRM free?

3Sigma mobile CRM is free to download, with no in-app purchases.

### Is Pen Book free?

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

### Do 3Sigma mobile CRM or Pen Book have ads?

Neither 3Sigma mobile CRM nor Pen Book shows ads.

### Which is updated more often, 3Sigma mobile CRM or Pen Book?

3Sigma mobile CRM ships an update every 8 days, and Pen Book weekly. Most recently, 3Sigma mobile CRM was updated on October 24, 2026 and Pen Book on October 24, 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.*