Comparison

King vs Prevent

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

King

This app provides a quick and objective sideline concussion screening test for athletes. It helps identify potential concussions by assessing eye movements, attention, and concentration through a simple number-reading exercise. Requires an existing King-Devick Online account.

Highlights
  • Objective sideline concussion screening
  • Assess eye movements and attention
  • Administer baseline and post-injury tests
  • Works offline
  • Suitable for ages 5+
Features
Read full description

This app is intended ONLY for users with an existing King-Devick Online account. The King-Devick Concussion Screening Test is an objective, remove-from-play sideline concussion screening test which can be administered by parents, coaches, athletic trainers or medical professionals in minutes. Peer reviewed published research has shown that the King-Devick Test is an accurate and reliable method to help identify athletes with concussion on the sidelines. It has particular relevance to sports such as football, hockey, soccer, and basketball in addition to all other contact or collision activities on the field or at home. The test involves reading aloud a series of single digit numbers from left to right on three test cards. The King-Devick can detect impairment of eye movements, attention, language, concentration and other areas which correlate with concussion. How does King-Devick Test work? -King-Devick Test account holders get unlimited concussion screening per athlete per year. -With the King-Devick Test App, you can administer baseline and post-injury assessments even when WiFi is not available. -All athletes establish a pre-season or pre-injury baseline test score annually. -Concussion screening for athletes as young as 5 years old.

About

Prevent

This app pairs with a special mouthguard to monitor head impacts in real-time. It provides detailed data on acceleration, direction, and load for each impact, helping teams and parents assess player safety and identify athletes needing evaluation.

Highlights
  • Real-time head impact data
  • Linear and rotational acceleration tracking
  • Impact direction and location analysis
  • Impact Load measurement
  • Player and team data views
  • Live alerts for high-magnitude impacts
Features
Read full description

The Prevent mobile app pairs with the Prevent Biometrics impact monitor mouthguard. The Prevent system provides near real-time, accurate head impact data to help teams make the right call about player safety. The Prevent app is designed for sideline monitoring of head impacts for the whole team, and is typically used by athletic trainers, coaches and athlete parents. For every head impact, see five key impact characteristics: * Linear acceleration of the head * Rotational acceleration of the head * Direction of the impact * Location on the head of the impact * Impact Load (a composite measure factoring impact count and magnitude) View head impact data on a player or team basis, and over the timeframe of a day, week or sports season. Introduce actionable, objective data into the process of identifying athletes needing sideline evaluation. The Prevent app provides live alerts of high magnitude head impacts. See athletes with high head impact exposure and instruct them on safer playing technique. Stand for smart play. The Prevent system helps you understand head impacts across the team and organization and be a leader in improving sports safety, performance and growing the game. This app requires at least one Prevent Impact Monitor Mouthguard to operate. Learn more at preventbiometrics.com or contact sales@preventbiometrics.com.

Screenshots

Prevent4 screens

Verdict

The call

The clearest difference is ratings volume: Prevent at 9 against King's 2. King's advantage is iOS requirement (9.0 vs 16.4). On price, rating, update cadence and ads there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

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

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 5.0 for King against 5.0 for Prevent. Both are backed by a comparable volume of ratings — 2 and 9 respectively.

UpkeepUpdate frequency

King ships an update every 2 months, Prevent monthly. The most recent releases landed on June 11, 2026 and September 1, 2026 respectively.

Scorecard2 real differences · 8 level
King versus Prevent: the parameters behind the verdict, then further details
ParameterKingPrevent
PriceFreeFree
Rating5.0 (2 ratings)5.0 (9 ratings)
Positive reviews—100.0% of reviews
Number of ratings29 — better
Update frequencyEvery 2 monthsMonthly — better
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPadiPhone, iPad — better
Requires iOS9.0 — better16.4
Further details — not scored
Size243 MB46 MB
Age rating4+4+
DeveloperKing-Devick Test LLCPrevent Biometrics, Inc

Customer experience

King

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

Prevent

All ratings9 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

King

No in-app purchases

None

Prevent

No in-app purchases

Questions

Is King free?
King is free to download, with no in-app purchases.
Is Prevent free?
Prevent is free to download, with no in-app purchases.
Which has better reviews, King or Prevent?
King and Prevent are both rated 5.0 out of 5 on the App Store, from 2 and 9 ratings respectively.
Do King or Prevent have ads?
Neither King nor Prevent shows ads.
Which is updated more often, King or Prevent?
King ships an update every 2 months, and Prevent monthly. Most recently, King was updated on June 11, 2026 and Prevent on September 1, 2026.

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