Reference
Glossary of spec terms
22 specifications that decide a purchase, in plain language -- and, for each one, what the number quietly leaves out.
Most bad purchases in these categories come from a specification that sounds decisive and is not. A compressor sold on peak pressure that cannot sustain flow. A trial period that looks generous until the return conditions are read. This page is the shared reference the portfolio sites will point back to, so no review has to re-explain the same term.
Where a figure below is unverifiable, that is stated rather than papered over -- the rule behind that is in the editorial policy, and the FAQ covers the broader question of how to judge any review site.
Electronics & audio
See the sites covering this category
- Active noise cancellation (ANC)
- Microphones sample ambient sound and the headphone plays an inverted waveform to cancel it out.
- What it leaves out. It works best on low, constant noise such as an engine drone, and barely at all on speech. A figure measured in a quiet test room says very little about a bus.
- IP rating
- Two digits describing ingress protection: the first is solids such as dust, the second is water. IPX7 means no dust rating and survival in one meter of water for thirty minutes.
- What it leaves out. It is a laboratory test with fresh water at a fixed pressure. It is not a promise about chlorinated pools, salt water, or a seal after two years of grit.
- Backhaul
- The link a mesh node uses to talk back to the main router, either over a dedicated radio band or over an ethernet cable.
- What it leaves out. Wired backhaul roughly transforms a mesh system. Reviews quoting mesh speeds rarely say which one they measured.
Automotive
See the sites covering this category
- Torque calibration
- Verification that a torque wrench delivers the force its scale claims, checked against a reference and adjusted if it has drifted.
- What it leaves out. A wrench out of calibration gives a confident number that is wrong, and nothing on the tool tells you. Some wrenches cannot be recalibrated at all, only replaced.
- Load rating
- The maximum weight a jack or stand is certified to hold, tested against a published standard with a safety margin built in.
- What it leaves out. The rating means little without knowing which standard it was tested to and whether anyone other than the manufacturer verified it.
Tools & DIY
See the sites covering this category
- Duty cycle
- The share of a ten-minute period a welder can run at a given current before it must cool. Sixty percent at 150A means six minutes on, four off.
- What it leaves out. Quoted at a current most buyers will not use, and at a stated ambient temperature. A hot garage in August reduces it.
- CFM and sustained flow
- Cubic feet per minute of air a compressor delivers. Sustained flow is what it can supply continuously, as opposed to peak pressure.
- What it leaves out. Compressors are marketed on peak PSI, but sustained flow is what decides whether an impact wrench keeps turning. The two are routinely confused.
Home improvement & safety
See the sites covering this category
- Cartridge standard
- The valve cartridge inside a faucet, which is the part that actually wears out. Some follow a common size; others are proprietary.
- What it leaves out. A cheap faucet using a standard cartridge outlives an expensive one with a proprietary cartridge the maker stops stocking after five years.
- Safe security rating
- A certification describing how long a safe resists a defined attack with defined tools, issued by a testing body.
- What it leaves out. Many safes are sold with no certification at all, using words like heavy-duty in place of a rating. An uncertified safe has no tested resistance.
Outdoor & garden
See the sites covering this category
- UV rating and fabric weight
- How much ultraviolet light a shade fabric blocks, and how much the fabric weighs per square meter. Weight is the better predictor of lifespan.
- What it leaves out. UV blocking is measured when new. The number that matters is how much the fabric has faded and weakened after a full year outdoors, which is rarely published.
- Wind rating
- The wind speed a structure is certified to withstand when correctly installed and anchored.
- What it leaves out. The most commonly missing figure in the category. Where a manufacturer does not publish one, that absence is itself the answer.
Baby & kids
See the sites covering this category
- Hip-healthy positioning
- A carrier design that supports an infant's thighs so the hips sit in a spread-squat position, rather than letting the legs dangle from the crotch.
- What it leaves out. Any carrier can claim to be ergonomic. Recognized assessment against published guidance is a different and much narrower claim.
- Folded dimensions
- The size of a stroller or travel cot once collapsed, which decides whether it meets an airline cabin limit.
- What it leaves out. Frequently quoted without the wheels or the seat unit attached. A complete folded measurement is a different number from the one on the box.
Sports & recreation
See the sites covering this category
- Range (electric transport)
- How far a scooter or e-bike travels on one charge, quoted under stated test conditions.
- What it leaves out. Quoted with a light rider on flat ground at low speed in mild weather. A hilly commute with a heavier rider in the cold can cut it by a third or more.
- Stud pattern
- The shape and arrangement of studs on a cleat, designed for a specific surface: firm ground, soft ground, artificial turf or indoor.
- What it leaves out. Wearing the wrong pattern for a surface is both slower and an injury risk. Marketing names for patterns are not standardized between brands.
Office & study
See the sites covering this category
- Cost per page
- Consumable cost divided by the pages a cartridge is rated to print, using the manufacturer's published yield.
- What it leaves out. The only printer number that matters, and it is almost never on the box. It can also change after purchase if firmware starts rejecting third-party cartridges.
- Page yield
- How many pages a cartridge prints, measured against a standardized test document at a fixed coverage.
- What it leaves out. The test document is not your document. Photos and heavy graphics consume far more, so treat yield as a comparison tool rather than a prediction.
Sleep
See the sites covering this category
- Foam density
- The weight of a foam per unit volume, which predicts how long a mattress keeps its shape rather than how firm it feels.
- What it leaves out. Frequently unpublished, and firmness scales are not standardized between brands, so a brand's medium is not another brand's medium.
- Trial period
- A window in which a mattress can be returned after sleeping on it.
- What it leaves out. Read the conditions. Minimum break-in periods, return shipping costs, original packaging requirements and restocking fees all narrow a generous-looking window.
Hobbies & crafts
See the sites covering this category
- Third-party compatibility
- Whether a machine accepts consumables, blades or materials from suppliers other than its manufacturer.
- What it leaves out. It is the difference between an affordable hobby and an expensive one, and it can be removed by a firmware update after you buy.
Home & kitchen
See the sites covering this category
- Clad base construction
- How the bottom of a pan is built up in layers, which determines how evenly it heats and how well it holds temperature.
- What it leaves out. Coating names are marketed heavily and base construction is barely mentioned, despite deciding most of how a pan actually cooks.
Workwear
See the sites covering this category
- Protection class code
- The letters and numbers on a safety boot describing toe protection, penetration resistance, slip rating and electrical properties.
- What it leaves out. Listings print the code without decoding it, so buyers match a boot to a job by guessing. The word safety in a product title means nothing on its own.
A term missing, or an explanation you think is wrong? Write to contact@magoomediagroup.com -- that counts as a correction and gets treated as one. How these specs get checked in practice is set out category by category.
Which site covers what you are buying?
Twenty-five sites across fifteen categories, each one narrow enough to go past the spec sheet.