How do you detect a mobile phone concealed inside a person?

Ferromagnetic detection responds to the magnetic mass inside a device — principally the speaker and vibration motor magnets — rather than to surface metal. That means it detects handsets carried, taped to the body, sewn into clothing or concealed internally, and a phone that is switched off, in flight mode or stripped of its battery is detected just the same. It emits nothing, so it is safe around pacemakers, implants and pregnant visitors and can be used repeatedly on the same people.

Can you detect drugs soaked into letters or clothing?

Yes, with explosives and narcotics trace detection rather than imaging. Impregnated paper and fabric look normal on an X-ray image but carry detectable residue, which is why custodial screening usually pairs trace detection with X-ray for property and post. RedteQ supplies, services and calibrates trace instruments across the major brands.

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Prisons · custody suites · secure hospitals

Screening For Prisons And Custodial Settings

Illicit phones drive continued offending from inside. Drugs arrive impregnated into paper and clothing. Both are routinely concealed in ways that no single technology will catch on its own, which is why a custodial search regime is built in layers.

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What You're Actually Trying To Stop

Custodial screening is the hardest detection problem on this list, because the people being screened have time, motivation and an established playbook.

Mobile phones and SIMs — used for drug supply, witness intimidation and escape planning, and concealed internally as a matter of routine.
Drugs, including impregnated material — soaked into letters, cards and clothing, where an image shows nothing and trace detection does.
Weapons and improvised blades — the traditional threat, and the one conventional detection handles well.
The volume problem — visits halls, staff entrances and admissions all move a lot of people, and a search regime that stops the day isn't sustainable.

Metrasens Ultra concealed item detection system screening people walking past — Ferromagnetic detection responds to magnetic mass — so a phone shows whether it is carried, taped on or concealed internally.

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What Works In A Custodial Setting

Layers, because no single technology covers phones, drugs and weapons at once.

Walk-Through Metal Detection

A Garrett Paragon on its custodial setting is the first layer for weapons and bulk metal, screening a moving queue without stopping the hall. Zone indication tells staff where to search.

Walk-through detectors →

Concealed Item Detection

The Metrasens Ultra finds phones taped to the body, sewn into clothing or concealed internally — and a handset that is switched off, in flight mode or with the battery out still shows.

Concealed item detection →

Drug Trace Detection

Trace detection identifies narcotics residue on hands, letters, clothing and property, including impregnated material that no X-ray image will reveal.

Trace detection →

Cabinet & Conveyor X-ray

Property, post and parcels screened on arrival, with cabinet units where floor space is tight and a conveyor where volume demands it.

X-ray range →

Just as important

What You Probably Don't Need

You don't need one box that claims to do all three. A walk-through metal detector finds weapons and bulk metal on a moving queue and does that job well — it is the layer most custodial sites should start with. What it was never built for is a handset concealed internally or narcotics soaked into a letter, and winding the sensitivity up doesn't change that; it just adds alarms on belt buckles. Phones need a technology that senses magnetic mass, drugs need trace rather than imaging, and property needs an image. Each layer covers what the others can't, which is why we specify them together rather than selling you one machine and calling the problem solved.

In practice

How It Runs Day To Day

Where the pressure is

Visits halls, reception and admissions, staff entrances, workshop and wing transitions — and portable enough to move when the intelligence changes.

Safe for everyone

Ferromagnetic detection emits nothing, so it is appropriate around pacemakers, implants and pregnant visitors, and repeatable daily.

Supported nationally

Multi-brand service and repair, parts on the shelf, and engineers who hold the clearances to work on secure sites.

Where X-ray is used for property and post, we recommend AI detection as standard — it flags weapons, ammunition and USB devices automatically, and does not have a bad shift. We supply and support screening across custodial and secure environments, alongside our work with government estates.

Phones, Drugs, Or Both?

Tell us what is getting in and where. We will tell you honestly which technology addresses it — and which doesn't.

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