# uSpectrum MK350N vs RPN

The clearest difference is price: uSpectrum MK350N at Free against RPN's $1.99. uSpectrum MK350N also leads on update cadence (every 2 months vs every 6 months) and iOS requirement (5.1.1 vs 12.0). On ads, in-app purchases and device support there is nothing between them.

uSpectrum MK350N is free to download; RPN costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

uSpectrum MK350N ships an update every 2 months, RPN every 6 months. The most recent releases landed on October 26, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | uSpectrum MK350N | RPN |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Rating | — | **[4.4 (14 ratings)](https://appshunter.io/ios/app/rpn-35-sd/id956224485/reviews)** |
| Number of ratings | — | **14** |
| Positive reviews | — | 71.4% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 6 months |
| Monetization | — | Paid |
| Size | 29 MB | 14 MB |
| Requires iOS | **5.1.1** | 12.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [United Power Research Technology Corporation](https://appshunter.io/developer/1501316337) | [CuVee Software](https://appshunter.io/developer/424873503) |

## What reviewers say

### uSpectrum MK350N

[App page](https://appshunter.io/ios/app/uspectrum-mk350n/id677053717)

**Features:** macOS Compatibility

**In-app purchases:** none


### RPN

[App page](https://appshunter.io/ios/app/rpn-35-sd/id956224485)

This app emulates the first pocket scientific calculator, offering a photo-realistic vintage experience. It simulates original operating speeds and unique arithmetic bugs, with optional modern enhancements like non-volatile registers.

**Highlights:** Photo-realistic look-and-feel, Multiple vintage skins, Vintage and Enhanced modes, Optional key-click and key-glow, Swipe to correct input, Display stack and memory registers

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is uSpectrum MK350N free?

uSpectrum MK350N is free to download, with no in-app purchases.

### Is RPN free?

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

### Do uSpectrum MK350N or RPN have ads?

Neither uSpectrum MK350N nor RPN shows ads.

### Which is updated more often, uSpectrum MK350N or RPN?

uSpectrum MK350N ships an update every 2 months, and RPN every 6 months. Most recently, uSpectrum MK350N was updated on October 26, 2026 and RPN on October 29, 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.*