# 数字空压站 vs Instrument Toolbox

The clearest difference is price: 数字空压站 at Free against Instrument Toolbox's $1.99. 数字空压站 also leads on iOS requirement (11.0 vs 13.0). Instrument Toolbox's advantage is update cadence (weekly vs every 2 months). On ads, in-app purchases and device support there is nothing between them.

数字空压站 is free to download; Instrument Toolbox costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

数字空压站 ships an update every 2 months, Instrument Toolbox weekly. The most recent releases landed on October 6, 2026 and September 23, 2026 respectively.

## The numbers

| Metric | 数字空压站 | Instrument Toolbox |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Weekly** |
| Monetization | — | Paid |
| Size | 76 MB | 8 MB |
| Requires iOS | **11.0** | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [苏州汇川技术有限公司](https://appshunter.io/developer/1441943965) | [立娜 王](https://appshunter.io/developer/1761096632) |

## What reviewers say

### 数字空压站

[App page](https://appshunter.io/ios/app/id6447392098)

**Features:** macOS Compatibility

**In-app purchases:** none


### Instrument Toolbox

[App page](https://appshunter.io/ios/app/instrument-toolbox/id6698856248)

A professional calculator designed for industrial control, automation, and instrumentation engineers. It offers quick conversions and calculations for gas concentration, units, steam properties, flange levels, and pipeline flow. Ideal for both field debugging and engineering design.

**Highlights:** PPM to mg/m³ conversion with compensation, Industrial unit conversion (pressure, volume, temp, etc.), Saturated steam pressure and density calculator, Flange level migration calculations, Pipeline flow and velocity calculator, Real-time calculation results

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

**In-app purchases:** none


## Frequently asked questions

### Is 数字空压站 free?

数字空压站 is free to download, with no in-app purchases.

### Is Instrument Toolbox free?

Instrument Toolbox costs $1.99, with no in-app purchases.

### Do 数字空压站 or Instrument Toolbox have ads?

Neither 数字空压站 nor Instrument Toolbox shows ads.

### Which is updated more often, 数字空压站 or Instrument Toolbox?

数字空压站 ships an update every 2 months, and Instrument Toolbox weekly. Most recently, 数字空压站 was updated on October 6, 2026 and Instrument Toolbox on September 23, 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.*