Lighting and electronics

IP rating

Also called ingress protection, IPX4, IPX7, IP67

What is an IP rating?

An IP rating states how well a device resists solids and water, under the IEC 60529 standard. The first digit covers dust and the second water, so IPX4 is splash resistant, IPX7 survives brief submersion, and IP67 does both.

IPX4: Splashes from any direction
IPX7: 1 m submersion, 30 minutes
IP67: Dust tight plus IPX7

What the two digits mean

The format is IP followed by two digits. The first is protection against solid objects and dust, on a scale to 6. The second is protection against water, on a scale to 9. An X in either position means that property wasn't tested, which is why headlamps so often read IPX4 rather than IP44.

The water ratings worth knowing

The water numbers are the ones to know. IPX4 covers splashing from any direction, which is rain. IPX6 handles powerful water jets. IPX7 means submersion in one meter of water for thirty minutes. IPX8 goes deeper, to a depth the maker specifies.

What you need for hiking

For hiking, IPX4 is genuinely enough for a headlamp in rain, and IPX7 is worth having if you're out in real weather or likely to drop the lamp in a creek while filtering. Two things to keep in mind: the ratings are tested with fresh water and say nothing about salt or dust-laden runoff, and they're tested on a new device. Seals age, and a battery door that has been opened a few hundred times is no longer the thing that was tested.

What each digit covers

The first digit runs 0 to 6 for solids: 5 is dust protected, meaning some ingress is allowed but not enough to interfere, and 6 is dust tight. An X in that position means the maker did not test it, not that it failed.

The second runs 0 to 9 for water. 4 is splashing from any direction, 5 and 6 are water jets of increasing force, 7 is immersion to one meter for thirty minutes, and 8 is deeper immersion on terms the manufacturer specifies. So IP67 means dust tight and briefly submersible.

What ratings outdoor electronics actually carry

Headlamps most often carry IPX4, which is rain, with better models at IPX7 or IP67. GPS watches are usually rated by water resistance in atmospheres rather than IP, and satellite messengers commonly land at IPX7. Power banks and speakers are the category where the rating varies most and matters most.

For hiking, IPX4 is genuinely sufficient for a headlamp used in rain. IPX7 is worth paying for on anything that might end up in a creek crossing or at the bottom of a wet pack.

What this means when you're choosing

IPX4 as the floor for anything used in rain
IPX7 if it will be dropped in a creek or used in sustained downpours
An X in the first position, which means dust was simply not tested

The common mistake

Reading IPX7 as better than IPX6 for rain

The scale is not strictly cumulative. IPX7 tests brief submersion in still water; IPX6 tests powerful water jets. A device can pass one and not the other, which is why some are rated IP67 and some IPX6 only.

Common questions

Is IPX4 enough for hiking in the rain?

Yes, for a headlamp. IPX4 covers splashing from any direction, which is what rain is. Step up to IPX7 if you expect to drop it in water or hike in sustained heavy weather.

What does the X mean in IPX7?

That the dust resistance wasn't tested or isn't being claimed. It doesn't mean the device has none, only that the maker hasn't rated it.

Where this is defined

IEC 60529, degrees of protection provided by enclosures, International Electrotechnical Commission

Where this comes up

Guides on Tom's Hiking where ip rating changes which product is right for you.

More in lighting and electronics

Lumens

Lumens measure the total light a headlamp emits in all directions. It's the headline number on every box and it says nothing about where that light goes, so a 400 lumen lamp with a bad beam can be less useful than a 200 lumen one with a good one.

Beam distance

Beam distance is how far a headlamp usefully projects light, quoted in meters. The industry standard measures it to the point where illumination falls to 0.25 lux, roughly the brightness of a full moon, which is dimmer than most people picture.

Flood vs spot beam

A flood beam spreads light wide and close for camp tasks and slow ground. A spot beam concentrates it into a narrow cone that reaches further, for seeing ahead at speed. Most trail headlamps mix both, and the mix matters more than the lumen count.

Regulated output

A regulated headlamp holds a steady brightness as its battery drains, then drops off sharply near the end. An unregulated one fades continuously from the moment you switch it on, so it's dim long before the battery is actually empty.

Reactive lighting

Reactive lighting uses a sensor to measure reflected light and adjusts brightness automatically, dimming when you look at a map and brightening when you look down the trail. It extends battery life and can feel unpredictable at speed.

Red light mode

Red light mode is a dim red setting on a headlamp that lets you see nearby things without spoiling your night vision. Your eyes take 20 to 40 minutes to adapt fully to the dark, and white light undoes that in seconds, while dim red light barely disturbs it.

Watt-hours (Wh)

Watt-hours measure how much energy a battery stores: voltage multiplied by capacity in amp-hours. Unlike mAh, which is quoted at the cell's own voltage, watt-hours let you compare any two batteries fairly, and they are the unit airlines use to set carry-on limits.

GPX file

A GPX file is the standard open format for storing GPS routes, tracks and waypoints as plain text. It's what you download from a trail site and load onto a watch or phone, and almost every mapping app and GPS device reads it.

Breadcrumb navigation

Breadcrumb navigation draws your loaded route as a line on a blank screen with an arrow for your position, without any underlying map. It tells you whether you're on the route, and nothing about what's around you.

ABC sensor

ABC stands for altimeter, barometer and compass, the three sensors in an outdoor watch. The altimeter and barometer are the same pressure sensor read two ways, and the compass is a magnetometer that gives you a heading when you're standing still.

Exit pupil

Exit pupil is the width of the beam of light a binocular sends to your eye, found by dividing the objective lens size by the magnification. An 8x25 has a 3.1mm exit pupil and an 8x32 has 4mm; the bigger number looks brighter in dim light.

Eye relief

Eye relief is how far behind a binocular's eyepiece your eye can sit and still see the whole field of view, measured in millimeters. Glasses hold your eye farther back, so hikers who wear them need about 15mm or more to avoid a view ringed in black.

ED glass

ED glass, short for extra-low dispersion, is lens glass that bends red, green and blue light by nearly the same amount. In binoculars it cuts the purple and green fringes around dark edges against a bright sky, so the image looks sharper and truer in color.

By Tom · Last reviewed August 13, 2026. Back to the glossary