Splint
Offline wilderness first aid
Only for iPhone
$2.99
iPhone
236 offline entries, 40 vector diagrams, 6 field tools. Search the way you'd actually say it. One-time purchase, no ads, never goes online.
A complete wilderness safety handbook that works with no signal. Everything ships inside the app — no downloads, no account, no network. Built for the moment your phone stops being a phone.
WHY IT ISN'T JUST AN E-BOOK
When something goes wrong you don't know what the condition is called. You know "he keeps shivering", "I've only got a plastic bag", "it's getting dark". So there is no nested table of contents — there are seven ways in: by situation, symptom, terrain, season, what you happen to be carrying, kind of knowledge, and urgency.
THREE THINGS MOST PEOPLE GET WRONG
· Satellite SOS is not a plan. It depends on your phone model, your country and a clear view of the sky, and plenty of phones have no satellite hardware at all.
· Bars on the screen don't mean a call will connect. In the backcountry an emergency call often fails even when the phone looks alive.
· But GPS is a one-way satellite broadcast and needs no cell network. A blank map only means the tiles can't download — your coordinates are still valid, and you can read them out.
WHAT'S INSIDE — 236 ENTRIES
· 12 decisions: the first thing to do when you realize you're lost; stay put or walk out; what order to do things in the last 90 minutes of daylight
· 42 first aid: hypothermia, heat stroke, drowning, snakebite, stings, mushroom poisoning, lightning, bleeding, CPR, fractures, frostbite, altitude illness
· 58 skills: finding and treating water, fire, insulation and shelter, signaling, direction-finding, knots, edibility
· 21 physics: why what's under you matters more than what's over you; why boiling water at altitude isn't the same as sterilizing it
· 13 improvised gear: plastic bag, foil, glasses, laces, the vehicle — people in trouble usually carry nothing
· 26 hazards · 22 weather · 12 trip preparation
· 30 myths debunked — probably the most useful chapter here
MYTHS, FOR EXAMPLE
· Drowning people can't shout and don't wave. The instinctive drowning response is silent and lasts 20 to 60 seconds.
· Don't rub the limbs of a moderate or severe hypothermia casualty, and don't give them drinks.
· Never hang a drowning victim upside down to "drain" them — it only delays CPR.
· Never cut, suck, ice or apply a tourniquet to a snakebite.
· "Bright colors mean poisonous" — every folk test for mushrooms is unreliable.
DIAGRAMS FOR THE THINGS YOU BUILD
Solar still, improvised filter, leaf-bed cross-section, three fire lays, lens ignition optics, signal-mirror aiming, shadow-stick direction, finding Polaris. Forty vector diagrams — sharp at any size, readable in red night mode.
SIX OFFLINE TOOLS
Compass, cross-checked against the sun's azimuth · Coordinates in decimal and DMS · Daylight-left countdown, computed locally · SOS flash, flashlight and screen together · Rescue whistle, synthesized live and far cheaper than shouting · Signal-mirror aiming
BUILT FOR THE FIELD
· Red night mode protects your dark adaptation — you can still see the trail afterward
· The screen stays awake while you read a procedure, and only then
· Steps are checkable, so you can pick up where you left off
· A permanent battery reminder: the phone is your only navigation and signaling device
UNITS AND REGIONS
Distances and temperatures are given in both metric and imperial. Content is written for North American and European backcountry — emergency numbers (911 / 112 / 999 / 000), venomous species, bear response by species and seasonal references are region-appropriate, not translated.
ABOUT THE SOURCES
First-aid and poisoning entries are written only from guidelines published by official bodies and professional societies, and every entry cites its sources. This is reference material for laypeople: it does not diagnose, gives no drug dosages, and is no substitute for professional medical care, professional rescue, or training. If you can get to definitive care, go.
One-time purchase. No ads, no in-app purchases, no subscription, no account, no analytics, and no network requests of any kind.
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New name: Splint. Nothing else has changed — the same 236 offline entries, 40 diagrams and 6 field tools, still working with no signal, no account and no network.
The developer, 伟强 夏, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- 伟强 夏
- Size
- 3 MB
- Category
- Reference
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later.
- iPhone
- Languages
- English and Simplified Chinese
- Age Rating
16+
- 16+
- Frequent
Medical Treatment information
Infrequent
Alcohol, Tobacco, Drug Use or References
- Copyright
- © 2026 夏伟强
