Most product listings are not lying. They are quoting the one number that flatters the product, in a unit you cannot compare, and leaving out the one that decides it. Here is what each of them measures, and what to ask for instead.
Every figure here comes from a manufacturer’s own published data, checked on a stated date, or is recorded as an absence that was actually looked for. Where we got one wrong, that is on corrections. How the assessments are made is in how we test.
Vacuums and blowers
- What it measures
- Output calculated at the instant of maximum current draw — which in practice is the moment the motor is stalling and about to stop.
- What it does not tell you
- Anything the machine can sustain. 2.8 HP is 2,088 W, and the Kärcher WD 3 that advertises it has a rated input of 1,000 W. The headline figure is roughly twice what the machine draws from the wall, so it cannot be delivering it.
- Ask for this instead
- Rated input power in watts, airflow in CFM, and suction in mbar or kPa. Kärcher publishes 1,000 W, 95 CFM and 215 mbar for the same machine.
Where this comes from: Kärcher's own technical data table and the retail listing title, both read 2026-09-17. Peak horsepower is a category-wide convention rather than one maker's invention. Kärcher WD 3 review works through it.
Vacuums and blowers
- What it measures
- Vacuum: the pull at the nozzle when airflow is fully blocked. It is what pulls grit out of a seat seam.
- What it does not tell you
- Airflow, which is the other half and does a different job — moving loose material along the hose. A machine can be strong on one and weak on the other, and cordless vacuums are usually sold on vacuum alone.
- Ask for this instead
- Both numbers, in the same units. Divide mbar by ten to get kPa: the Kärcher's 215 mbar is 21.5 kPa, against the 13 kPa Fanttik publishes for the V8 Mate.
Where this comes from: Fanttik V8 Mate record, verified 2026-09-03; Kärcher WD 3 record, re-read 2026-09-17. No airflow figure appears in the specifications recorded here for the Fanttik. Kärcher WD 3 review works through it.
USB-C and charging
- What it measures
- How much power the cable is rated to carry. Nothing else.
- What it does not tell you
- How fast data moves through it. Power and data travel on separate conductors, so the two are independent. Baseus publishes 100 W and 480 Mbps on the same product page for the Free2Pull Mini — 480 Mbps is USB 2.0, unchanged since 2000.
- Ask for this instead
- The data rate in Gbps. 480 Mbps means USB 2.0 and no high-speed pairs, so that cable can never carry video however many watts it is rated for.
Where this comes from: Baseus's own product page for the Free2Pull Mini, read 2026-09-17. An earlier record here wrongly said Baseus published no data rate; that was a failed search, and the correction is public. Baseus Free2Pull Mini review works through it.
USB-C and charging
- What it measures
- What the cable can carry, given a source port that can produce it.
- What it does not tell you
- Whether your port can. A USB-C socket carries video only if it supports DisplayPort Alt Mode, Thunderbolt or USB4, and no cable can add a capability the port does not have.
- Ask for this instead
- The phrase 'DisplayPort Alt Mode', 'Thunderbolt' or 'USB4' against that specific port in your machine's own specification. Cable Matters states the requirement outright, and that it will not work on a power-only or data-only hub port.
Where this comes from: Cable Matters' product page for model 201036, read 2026-09-17, including its own stated incompatibilities. USB-C charges but the monitor stays black works through it.
USB-C and charging
- What it measures
- The total the charger can deliver across all of its ports at once.
- What it does not tell you
- What any single port gives you once a second device is plugged in. The listing for the Baseus 65 W GaN unit states 45 W + 20 W across the dual USB-C ports — so the first port drops to 45 W the moment you use the second.
- Ask for this instead
- The per-port split when every port is occupied. If a maker publishes only a total, assume the split is the worst one that adds up.
Where this comes from: Baseus 65 W GaN charger record. The split is a listing claim rather than manufacturer documentation, and is recorded here as such — Baseus sells several units described as a 3-port 65 W. Charging four things from one hotel socket works through it.
USB-C and charging
- What it measures
- Charge capacity, at a voltage the listing usually does not state.
- What it does not tell you
- How long the thing runs, and how it compares with anything at a different voltage. mAh is only comparable within one voltage; watt-hours are comparable across all of them, which is also the unit airlines use.
- Ask for this instead
- Watt-hours, or the runtime at the setting you will actually use. Fanttik publishes both for the V8 Mate: 17 minutes on high, 30 on low.
Where this comes from: Fanttik V8 Mate record, verified 2026-09-03 against the manufacturer listing.
Cordless tools
- What it measures
- How long the battery lasts. On a cordless pressure washer, that is all it measures.
- What it does not tell you
- How long the water lasts, which is what actually stops the job. The Fanttik NB10 Fold holds 3.17 gallons, and Fanttik publishes no flow rate — so the tank cannot be converted into a working time at all, and water runs out long before the cell does.
- Ask for this instead
- Flow rate in litres or gallons per minute. Without it, tank capacity and battery runtime cannot be reconciled and the one question a buyer has is unanswerable.
Where this comes from: Fanttik's own specification page, read 2026-09-16. The absence of a flow rate is recorded as an absence, having been looked for. Fanttik NB10 Fold review works through it.
Cordless tools
- What it measures
- The highest of the machine's settings.
- What it does not tell you
- What you get on the setting you will actually use. The same unit has three modes — 100, 160 and 220 PSI — and a single headline number describes one of them.
- Ask for this instead
- The full range, and which mode the manufacturer's runtime figure was measured at.
Where this comes from: Fanttik NB10 Fold record, corrected 2026-09-16 after the record carried only the maximum. Fanttik NB10 Fold review works through it.
Cordless tools
- What it measures
- The bare tool, with no battery in it.
- What it does not tell you
- What you will hold. On an 18 V platform the battery is a substantial part of the mass, and it is sold separately — so the figure that decides whether a cordless inflator beats a 12 V compressor is not the one printed.
- Ask for this instead
- Weight with the battery you intend to use, and the duty cycle. RYOBI publishes 1.35 lb and 0–150 PSI for the ONE+ inflator, and no duty cycle.
Where this comes from: RYOBI's published figures, 2026-09-13. This record previously carried an unsourced 2.5–2.9 lb — roughly double — and the correction is public. 12 V compressor vs cordless inflator works through it.
PC building
- What it measures
- Nothing measurable. It is an adjective, and it is the one to be most careful with on a component that sits millimetres from live pins.
- What it does not tell you
- The figures behind it. ARCTIC's own page for the MX-6 publishes neither 'carbon-based' nor 'non-conductive and non-capacitive' — it publishes 1.8 × 10¹² Ω-cm volume resistivity and a 7.5 kV/mm breakdown voltage, which is the measurement the adjective is standing in for.
- Ask for this instead
- Volume resistivity and breakdown voltage. Also note ARCTIC deliberately publishes no W/mK figure for this paste at all, and says so.
Where this comes from: ARCTIC's product page, 2026-09-13. Three pages on this site asserted the adjectives before that check and were corrected. Thermal paste vs thermal pads works through it.
PC building
- What it measures
- Airflow into open space, with nothing in the way.
- What it does not tell you
- How the fan behaves against resistance — a radiator, a dust filter, a dense heatsink. That is static pressure, and it is a separate published figure: ARCTIC gives 2.2 mmH₂O for the P12 alongside the 56.3 CFM.
- Ask for this instead
- Both. A high-CFM, low-pressure fan moves a lot of air across a case and very little through a radiator.
Where this comes from: ARCTIC P12 PWM PST record, verified against ARCTIC's own page. ARCTIC P12 review works through it.
PC building
- What it measures
- Perceived loudness on a scale where doubling the number means roughly twice as loud to a listener.
- What it does not tell you
- Any comparison with the dB(A) figure every other maker prints. ARCTIC publishes Sone for the P12 and no dB(A) at all, which makes the honest figure the hard one to shop with.
- Ask for this instead
- dB(A) at a stated distance and RPM, or accept that you are comparing across incompatible units and say so.
Where this comes from: ARCTIC P12 PWM PST record. The absence of a dB(A) figure was looked for, not assumed. ARCTIC P12 review works through it.
Car batteries
- What it measures
- Charging current, which sets how long a given battery takes to fill.
- What it does not tell you
- Which batteries it is rated for. NOCO publishes 1 A and 'batteries up to 30 Ah' for the GENIUS1; CTEK publishes 4.3 A and 1.2–110 Ah for the MXS 5.0. The amp figure alone does not tell you whether the charger suits your car.
- Ask for this instead
- The Ah range the maker rates it to charge, and separately to maintain — CTEK rates the MXS 5.0 to maintain up to 160 Ah while charging up to 110 Ah.
Where this comes from: CTEK and NOCO records, both from the manufacturers' own published figures. CTEK MXS 5.0 vs NOCO GENIUS1 works through it.
Car batteries
- What it measures
- A different voltage profile — CTEK publishes 14.7 V for AGM against 14.4 V normal.
- What it does not tell you
- Any difference in current, and any suggestion that one charger is 'the AGM charger'. Both of the chargers above offer AGM modes, so chemistry does not separate them.
- Ask for this instead
- Capacity in Ah and how the car is used. Size the charger on those; the chemistry mode is a setting, not a product category.
Where this comes from: CTEK MXS 5.0 record: 14.4 V normal, 14.7 V AGM, 15.8 V RECOND. CTEK MXS 5.0 vs NOCO GENIUS1 works through it.
Ratings and claims
- What it measures
- Two separate things. The first digit is solids — 6 means dust-tight. The second is water — 5 means low-pressure jets from any direction.
- What it does not tell you
- Submersion, which needs a 7 or 8 in the second position, and any promise about hot water, steam or solvents. CTEK publishes IP65 for the MXS 5.0 and NOCO publishes IP60 for the GENIUS1 — the same dust rating and no water rating at all.
- Ask for this instead
- Both digits, and note that a higher second digit is not always a superset of a lower one.
Where this comes from: CTEK and NOCO records, from the manufacturers' published figures.
Ratings and claims
- What it measures
- That the joint moves through a wide range. It is a statement about the mechanism's travel, and travel is genuinely useful on a mirror you are pushing into a gap you cannot see into.
- What it does not tell you
- Whether it stays where you put it, which is the entire question for an inspection mirror held under a car. Ullman states that the A-2T 'can be adjusted to nearly any angle' and does not claim the joint holds that angle.
- Ask for this instead
- An explicit statement that the joint holds position under its own weight. If a maker had it, they would print it.
Where this comes from: Ullman's own page, 2026-09-13. A record here previously asserted the hold-angle claim; it was wrong, five pages repeated it, and the correction is public. Dropped a bolt into the engine bay works through it.