This is my third Nitecore flashlight. I primarily use my SRT7GT as an everyday multi-purpose light to throw a tighter beam at distance and purchased this for an everyday flood-light. I saw some reviews complaining about how it's "Not 4000 Lumens" with one showing this flashlight next to their other 1800-Lumen light. Another was knocking the flashlight for the beam not reaching as far as they thought it should. Along with other information that lacks context or reference to why, I thought I'd share a bit of information that can help decipher why and help you buy the kind of light you're looking for. This is just one of thousands out there, it's a fantastic flashlight for it's intended use. Just like any other tool, it's designed to operate for a specific purpose. You wouldn't use a Phillps-head screwdriver in a Flat-head screw and say "The Phillps screwdriver is terrible!" right? :)1.) This light has two control schemes. "Daily" and "Tactical". The light is set to "Daily" out of the box.2.) Daily mode uses a memory function to remember the previous brightness levels between On/Off cycles and Tactical Mode always turns on in "Turbo Mode" when it's powered on, regardless of it's previous brightness level when it last turned off.3.) Daily Mode cycles through the following brightness levels in the following order: Ultra Low 2 Lumen / Low 50 Lumen / Mid 300 Lumen / High 850 Lumen / Higher 1700 Lumen / Turbo* 4000 lumen (More on this in point number five.)4.) Tactical Mode cycles though the following brightness levels in the following order: Turbo 4000L / High 850L / Mid 300L / Low 50L5.) To enable the use of the 4000 Lumens in "Daily" mode, you must turn on the flashlight (doesn't matter which brightness setting it is on.) and hold down the flat "Mode" button on the tail cap. The highest brightness in Daily mode without holding the button down is 1700 Lumens. (This is why it looks the same as their 1800 lumen flashlight in another review.)6.) Turbo Mode is for use for short bursts of high output light, it cannot sustain such a high brightness for more than maybe 30sec depending on ambient temperature and the current temperature of the flashlight. Due to the small size of this light, it's very limited in it's heat dissipation. If you power on the turbo function, it only takes about a second or two up against your skin to find out how scorching hot the LEDs and circuitry gets. This isn't a defect, it's just the trade off you get when packing so much power into a such a small package. The P20iX has protection built in with one being heat protection to prevent damage to the LEDs, the Solder Joints, the Circuitry, and the Battery. After those 30sec or so, the flashlight will gradually reduce the power, lowering the brightness, to prevent damage to the flashlight and injury to the operator.7.) The P20iX in terms of functionality is more akin to a floodlight and not a spotlight. The packaging of four LEDs in a small head and shallow reflectors can't throw light as far as flashlight with a large head and deep reflector. This 4K lumen flashlight has a max beam intensity of 12,200 candela. Whereas my SRT7GT 1K lumen flashlight has a max beam intensity of 50,900 candela. The P20iX isn't designed to be a spot light, it's designed to be a super bright flood-style everyday light for use at relatively short distances that covers a vast area. The SRT7GT is designed to be a bright throw-style light used to provide more focused light over a longer distance.8.) To the person who stated their 168 lumen Maglite was brighter: There are only two possibilities for this outcome, and one is that the flashlight you received was defective.9.) "I want a flashlight that's better for X, Y, and Z; How can I tell the difference?" There are many factors that determine how the usable light from a flashlight will be distributed in what type of beam and at what distance. To avoid the deeper discussions, we can stick to a few basics:-Brightness: This one is simple, the higher the lumen/candela the more light producted.-Reflector Shape: Dominant factor for the pattern of light, with most flashlights being cone-shaped.-Reflector Depth: Dominant factor for the the intensity of the available light and the travel distance.-Reflector Texture: Smooth for better focus and intensity / Orange peel for more even spill and coverage.Once you get a good handle on how these factors affect the light, you'll be able to get a general understanding on how the light will perform for a given task before you even try it. You'll know if it's designed to provide a small beam at long-distances or a wide beam at close quarters, or any variation in-between.Not trying to defend bad products when they're just straight up bad; There's so many out there it's ridiculous. However many times when someone has a bad experience with a reputable product that is functioning properly, as apposed to being defective, it's simply an issue of what they expected vs what they received. When all the information including specifications and designs are telling you exactly what to expect, any discrepancy thereafter is usually due to 'ignorance' on how to functionally apply that information. (Used in the literal sense of the word, it's not in any way an insult.)When shopping for a light, consider these specifications to help you find the perfect light for you.-Lumen: Higher number = More light output / Higher heat / More power drain / Higher cost-Throw: Larger Number = Usable light reaches further to be able to view things at a greater distance.-Max Intensity: The highest amount of light focused within a given point of the beam pattern at a given distance.Don't fall for scams like 1000K lumens lights for $10 or 1,000,000 lumens for any amount of money... At the time of typing this, the brightest handheld flashlight in the world is the Imalent MS18 at 100,000 lumens. This light requires 8x 21700 Batteries and uses a heat pipe radiator along with a cooling fan to make it usable. It's easy to see that a 1,000,000 flashlight using a single battery in small form factor is impossible.All-in-all, I bought this light for a specific use and it's performance flawlessly. My only gripe is that if you cycle the brightness modes too quickly it can initiate the strobe feature which annoying but easily resolved by me not being impatient and spamming the button at 'light speed'. -Apologies, couldn't help it.-