The IP rating is the spec everyone scrolls past — right up until a light dies in the rain, or quits the first time it hits the driveway. After years of carrying a light through Idaho winters, wet hikes and the occasional drop, I’ve learned that durability specs are the quiet difference between a light you trust and a paperweight. Here’s how IP and impact ratings actually play out in real use, and the part nobody mentions: what cold does to all of it.
IP ratings, decoded
The IP rating is two characters that tell you how sealed a light is. For flashlights, the one that matters is the water digit — you’ll usually see it written IPX4, IPX7, IPX8 (the X just means the dust rating wasn’t separately specified; quality lights are sealed against dust anyway).
- IPX4 — splash resistant. Survives splashing water from any direction. Fine for rain, a wet hand, a bit of weather. Not for submersion. A light that falls in a puddle and stays there may not make it.
- IPX7 — temporary submersion. Survives being submerged in about a metre of water for up to 30 minutes. This is the sweet spot for most carry and outdoor use: drop it in a creek, fish it out, keep going.
- IPX8 — sustained submersion. Rated beyond IPX7, to a depth and time the maker specifies. This is dive-and-water-work territory. Most people don’t need it, but it’s there if your life is genuinely wet.
In plain terms: IPX4 for “it’ll see rain,” IPX7 for “it might go underwater briefly,” IPX8 for “it lives underwater.” For an everyday carry light I want IPX7 as my baseline — rain is guaranteed, and “dropped it in a puddle” shouldn’t be a death sentence.
Impact rating: the drop you will eventually make
Right next to the water rating, FL-1 lists an impact resistance figure — the height in metres the light survived being dropped onto concrete in testing, typically 1 to 2 metres. This sounds minor until you remember that a pocket light gets dropped. Onto driveways, jobsite floors, parking lots. A 1-metre impact rating roughly covers “fell out of my hand standing up.” It’s not a promise it’ll survive anything, but it tells you the maker built and tested the thing to take a hit rather than shatter.
The lights that skip this rating entirely are usually the ones that don’t survive the fall. A reputable light with an honest impact figure has been built to keep working after the drop you’re definitely going to make eventually.
Where the seals actually fail
A rating is a starting point, not a guarantee for the life of the light. In real use, water resistance lives and dies on two things:
- The O-rings and threads. The seal is a rubber O-ring at every joint — tailcap, head, lens. Keep the threads clean and lightly lubed (per the maker’s guidance), and don’t cross-thread the tailcap. Most “waterproof” lights that leak failed at a dirty or pinched O-ring, not because the rating was a lie.
- Closing it properly. A light is only sealed when it’s done up. If the tailcap is a half-turn loose — which is also how some lights “lock out” to prevent accidental activation — it’s not at its rated seal. Snug it down before the rain.
The part nobody mentions: cold
Here’s what years of winter carry taught me that no IP rating tells you. Cold doesn’t attack the seals — it attacks the battery. Lithium-ion cells lose usable capacity and sag harder as they get cold. A light that runs two hours at room temperature can post noticeably less in genuinely cold weather, and a high-output mode can step down sooner because the cold cell can’t deliver current as freely.
What I actually do about it:
- Keep the spare cell warm. On a cold night, a spare 18650 in an inside pocket near my body stays warmer and performs better than one that’s been riding in an outside pocket. (Still in a cell case, always — loose cells never ride against keys or coins.)
- Expect shorter runtime and plan for it. I don’t trust the room-temperature runtime number on a freezing night. I bring a charged spare or a backup light.
- Let condensation settle. Bringing a cold light into a warm room can fog the lens or pull moisture in if a seal is imperfect. I let it warm up gradually rather than yanking the tailcap the second I’m inside.
None of this is exotic. It’s just the difference between a light that “should” last the night and one that actually does when it’s below freezing and wet.
How I’d shop durability
When I read a spec sheet for a light that’ll live outdoors:
- IPX7 as the carry baseline. IPX4 is fine for a purely indoor/urban light; IPX7 if rain and puddles are part of life; IPX8 only if you’re genuinely in the water.
- An honest impact rating — 1 metre minimum, because you will drop it.
- Then I factor in cold myself, because the spec sheet won’t: plan for less runtime and keep the spare warm.
Durability is the spec you don’t appreciate until the night you need it — wet, cold, after a drop, miles from a dry pocket. Buy the IP and impact ratings that match your actual life, and respect what cold does to the cell.
If you want the lights and cells that hold up to weather and a winter — honest FL-1 figures, real IP ratings, and the chargers behind them — the best 18650 flashlights guide is where I lay out the gear that earns its keep when the conditions turn.