"Waterproof" is a word manufacturers love and physicists hate. Drop it on a product page and it moves lights. But it doesn't tell you whether yours survives a rainstorm, a dropped-in-the-creek moment, or a full dunk off the side of a kayak. The spec that actually answers that question is the IP rating — and once you can read it, the marketing stops mattering.
Here's how to decode it, what the numbers really promise, and where lights leak even when the box says they shouldn't.
The IP code, digit by digit
IP stands for Ingress Protection, defined by the international standard IEC 60529. The rating is always two characters after "IP," and each one means something different.
- First digit (0–6): solids and dust. A 6 means fully dust-tight — nothing gets in. That matters more for a light that lives in a range bag or a toolbox than one that rides clean in your pocket.
- Second digit (0–8, sometimes 9K): water. This is the one flashlight buyers actually care about, and it is not linear. Jumping to an 8 is a far bigger deal than the gap between a 4 and a 5.
You'll often see an X in place of the first digit — IPX7, IPX8. That doesn't mean "no dust protection." It means the dust side simply wasn't formally tested. Plenty of well-sealed lights carry an IPX8 rating because the maker only paid to certify the water half.
The water numbers that matter
- IPX4 — splashing. Rain, sweat, a splash at the sink. Fine for a light that never goes under.
- IPX6 — pressurized jets. A hose, a pressure washer, heavy driving rain. Water can hit it hard from any direction and it keeps running.
- IPX7 — one meter, 30 minutes. Drop it in a puddle, a sink, or a shallow creek and fish it back out — it'll live.
- IPX8 — beyond one meter. Continuous submersion at a depth the manufacturer defines. This is where you see specs like "IP68, 2m": dust-tight and rated to two meters underwater.
That last point is the one people miss: IPX8 and IP68 do not specify a universal depth. The standard leaves it to the maker, which is why one IP68 light is good to two meters and another claims five. Always read the depth spec, not just the two digits.
What the rating doesn't promise
An IP rating is a lab result — controlled conditions, a light that's sealed, clean, and fully closed. Real life is messier, and that's exactly where lights leak.
- The o-rings. Every threaded joint — tailcap, head, battery tube — seals with a rubber o-ring. Let one dry out, nick it, or let grit build up on it and the rating is gone. This is the single most common failure point, full stop.
- Charging ports. A lot of USB-C EDC lights are only fully rated with the port cover closed. Charge the light, and until that flap is seated again you've got a hole straight to the electronics. Never plug in a wet light.
- Opening it wet. Crack the tailcap to swap a cell while the outside is still soaked and you've just invited water into the tube. Dry the light first, every time.
How much rating do you actually need?
Match the spec to how you carry, not to the biggest number on the page.
- Pocket EDC, dog walks, the occasional downpour: IPX4 to IPX6 has you covered. Most quality EDC lights clear this without thinking about it.
- Job sites, fishing, canoe and kayak, anything near open water: go IPX7 or IP68 so a drop in the drink is a shrug, not a funeral.
- Deliberate underwater use: you want an IP68 light with an explicit depth rating that comfortably exceeds where you'll take it — and if the maker offers a dual o-ring setup, use it.
Keeping the rating you paid for
Waterproofing degrades; it isn't permanent. A few habits keep it intact:
- Wipe the threads and o-rings clean, and re-lube the o-rings a couple of times a year with a dab of silicone grease. Dry, cracked rubber is a leak waiting to happen.
- Snug the tailcap and head down fully. A half-turn short breaks the seal.
- Keep a spare o-ring or two on hand. They cost pennies, and a torn one is the most likely thing to sideline an otherwise perfect light.
- Rinse salt water off with fresh water and dry the light before it goes back in the bag.
Where the brands land
The majors we stock publish real IP numbers, and most of their EDC and tactical lights land at IP68 with a stated depth. Fenix, Nitecore, and OLIGHT rate the bulk of their lineups to IP68, typically two meters — which is why they're the easy call when water is part of the job. Convoy leans more on thick gaskets and solid o-rings than on a certified number, so treat those as splash-and-dunk tough rather than dive gear, and keep the seals maintained.
Bottom line: ignore the word "waterproof" and read the two characters after IP. The first tells you about dust, the second about water, and the depth spec fills in the rest. Once you know the number you need, you can buy with confidence — start with our EDC flashlight collection and match the rating to where the light is actually going to live.