# King County EMS Protocol Book vs ER NAV

The clearest difference is in-app purchases: King County EMS Protocol Book at none against ER NAV's 1. King County EMS Protocol Book also leads on rating (5.0 vs 4.8) and iOS requirement (15.0 vs 17.5). ER NAV's advantage is ratings volume (16 vs 1). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. ER NAV sells 1 in-app purchase, starting at $2.99 per month. King County EMS Protocol Book asks for nothing beyond the download.

King County EMS Protocol Book holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: ER NAV has 16 ratings behind it against 1, so its average is the more settled of the two.

King County EMS Protocol Book ships an update every 4 months, ER NAV every 3 months. The most recent releases landed on November 3, 2026 and October 30, 2026 respectively.

## The numbers

| Metric | King County EMS Protocol Book | ER NAV |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/king-county-ems-protocol-book/id777118990/reviews)** | [4.8 (16 ratings)](https://appshunter.io/ios/app/er-nav/id6751308029/reviews) |
| Number of ratings | 1 | **16** |
| Positive reviews | — | 85.7% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 3 months** |
| Monetization | **Free** | Freemium |
| Size | 28 MB | 32 MB |
| Requires iOS | **15.0** | 17.5 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [Acid Remap LLC](https://appshunter.io/developer/323130617) | [DirectTo Solutions LLC](https://appshunter.io/developer/1834555580) |

## What reviewers say

### King County EMS Protocol Book

[App page](https://appshunter.io/ios/app/king-county-ems-protocol-book/id777118990)

Access emergency medical protocols and supporting materials offline. Quickly find information with indexed lookup and search, save favorites, and add custom notes. Stay updated with the latest protocols and hospital contact details.

**Highlights:** Offline protocol access, Indexed lookup, Search titles and text, Favorites tab, Customizable notes, Updated protocol information

**In-app purchases:** none


### ER NAV

[App page](https://appshunter.io/ios/app/er-nav/id6751308029)

This app provides EMS professionals with direct navigation to ambulance bays and critical hospital information. It offers features like specialty filtering, user-submitted bay images, and integrated medical references. Users can also access protocols, drug information, and a unique O2 tank calculator.

**Highlights:** Direct ambulance bay navigation, Hospital specialty designations, User-submitted bay images, Integrated medical references, NJ EMS protocol access, O2 tank duration calculator, Real-time traffic flow

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| All Access | $2.99 | per month |


## Frequently asked questions

### Is King County EMS Protocol Book free?

King County EMS Protocol Book is free to download, with no in-app purchases.

### Is ER NAV free?

ER NAV is free to download, with in-app purchases available.

### Which has better reviews, King County EMS Protocol Book or ER NAV?

King County EMS Protocol Book is rated higher. King County EMS Protocol Book averages 5.0 out of 5 from 1 ratings, while ER NAV averages 4.8 from 16 ratings.

### Do King County EMS Protocol Book or ER NAV have ads?

Neither King County EMS Protocol Book nor ER NAV shows ads.

### Which is updated more often, King County EMS Protocol Book or ER NAV?

King County EMS Protocol Book ships an update every 4 months, and ER NAV every 3 months. Most recently, King County EMS Protocol Book was updated on November 3, 2026 and ER NAV on October 30, 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.*