# Stack Testers Flow Friend vs My Second Line Text Voice Call

The clearest difference is in-app purchases: Stack Testers Flow Friend at none against My Second Line Text Voice Call's 11. Stack Testers Flow Friend also leads on ads (none vs shown) and iOS requirement (13.0 vs 15). My Second Line Text Voice Call's advantage is update cadence (every 4 weeks vs every 8 months) and review sentiment (27% vs 0%). On price and device support there is nothing between them.

Both are free to download. My Second Line Text Voice Call sells 10 in-app purchases, starting at $2.99 per 7 days. Stack Testers Flow Friend asks for nothing beyond the download.

Stack Testers Flow Friend ships an update every 8 months, My Second Line Text Voice Call every 4 weeks. The most recent releases landed on October 5, 2026 and October 19, 2026 respectively.

## The numbers

| Metric | Stack Testers Flow Friend | My Second Line Text Voice Call |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.7 (7.2K ratings)](https://appshunter.io/ios/app/my-second-line-text-voice-call/id1531644835/reviews)** |
| Number of ratings | — | **7.2K** |
| Positive reviews | 0.0% of reviews | **26.9% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 8 months | **Every 4 weeks** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 32 MB | 104 MB |
| Requires iOS | **13.0** | 15 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Lewis Holmes](https://appshunter.io/developer/1454834389) | [AutoBizLine, Inc.](https://appshunter.io/developer/1531644837) |

## What reviewers say

### Stack Testers Flow Friend

[App page](https://appshunter.io/ios/app/stack-testers-flow-friend/id1454834655)

This mobile toolkit assists environmental engineers with on-site calculations for stack testing. Quickly determine velocity and volume flow by inputting stack size and gas conditions, eliminating the need for manual calculations or laptops. It also aids in calculating differential pressure cell mA output for data logging.

**Highlights:** Velocity and volume flow calculations, Input stack size and gas conditions, Differential pressure cell mA output calculation, Preloaded Engineers Note Book content, On-site calculation tool

**Features:** macOS Compatibility

**In-app purchases:** none


### My Second Line Text Voice Call

[App page](https://appshunter.io/ios/app/my-second-line-text-voice-call/id1531644835)

Obtain a secondary phone number for your smartphone, offering both local and international options. This app provides private calling and texting capabilities, ideal for personal use or business needs, with features like voicemail transcription and auto-reply.

**Highlights:** Get a USA/Canada local number, International phone numbers, Transfer your current phone number, Easy texting and quality phone calls, Private personal communications, Professional business team number, Voicemail transcription

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

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Receive verification code | $2.99 | per 7 days |
| Upgrade for MMS | $3.99 | per month |
| Weekly Plan Promotion | $3.99 | per 7 days |
| Weekly Plan | $5.99 | per 7 days |
| Monthly Plan | $8.99 | per month |
| Receive Verification Codes | $9.99 | per month |
| Toll Free Number Weekly Plan | $9.99 | per 7 days |
| US Local Phone Number | $9.99 | per 7 days |
| Weekly Plan | $14.99 | per 7 days |
| Change another phone number | $9.99 | one-time |

**What reviewers like**

- 🚀 Easy to use
- 👍 Convenient for business
- 🚀 Quick setup
- 👍 Helpful for verification codes
- 👍 Reliable service

**What reviewers complain about**

- 💰 Expensive subscription
- 🐛 Numbers not working as expected
- 🔒 Privacy concerns
- 🐛 Unreliable service
- 💰 Hidden fees

**Reported bugs**

- Numbers not working for verification
- App crashing or freezing
- Subscription issues and lack of refunds
- Inconsistent service quality

**Requested features**

- Ability to import existing numbers
- Support for more countries
- Improved customer support
- Clearer pricing and subscription details


## Frequently asked questions

### Is Stack Testers Flow Friend free?

Stack Testers Flow Friend is free to download, with no in-app purchases.

### Is My Second Line Text Voice Call free?

My Second Line Text Voice Call is free to download, with in-app purchases available.

### Do Stack Testers Flow Friend or My Second Line Text Voice Call have ads?

My Second Line Text Voice Call shows ads; Stack Testers Flow Friend does not.

### Which is updated more often, Stack Testers Flow Friend or My Second Line Text Voice Call?

Stack Testers Flow Friend ships an update every 8 months, and My Second Line Text Voice Call every 4 weeks. Most recently, Stack Testers Flow Friend was updated on October 5, 2026 and My Second Line Text Voice Call on October 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.*