Skip to content
AkerminMeasure. Monitor. Improve. Compare Products
Learning Center

What Is a Borescope and When Is It Useful?

A borescope puts a small lit camera on the end of a flexible or rigid probe and shows the picture on a screen or phone. It answers the question a thermal camera and a moisture meter both leave open: what is actually in there?

By the Akermin Editorial Team · 3 min read

A borescope, also called an inspection camera or endoscope, is a small camera and LED light on the end of a probe, connected to a screen or a phone. It lets you look inside wall cavities, ducts, drains, engines, machinery and appliances through an opening a few millimeters across. Where a thermal camera shows a pattern on a surface and a moisture meter gives a number, a borescope shows the thing itself: the wet insulation, the blocked duct, the chewed cable, the corroded fitting.

Parts and choices

  • Probe. Flexible probes snake around bends but are hard to aim; semi-rigid probes hold a shape you bend into them and are easier to push through cavities; articulating probes have a steerable tip controlled from the handle, the most useful and the most expensive.
  • Diameter. 8 mm is common and gives the best image; 5.5 mm fits more places; 3.9 mm and below reach spark plug holes and tight gaps at the cost of resolution and light.
  • Camera and focus. Resolution from 640×480 to 1080p and beyond. Fixed focal distance, typically 30 to 100 mm; dual-lens models add a side camera for looking at walls of a pipe or cylinder.
  • Lighting. Adjustable LEDs around the lens. Too much light washes out close objects; adjustable brightness matters.
  • Display. Built-in screen (no phone needed, works with gloves) or Wi-Fi/USB to a phone (bigger screen, easy sharing).
  • Length. 1 to 2 m for walls and engines; 5 to 15 m for drains and ducts, where a stiffer probe helps.
  • Waterproofing. IP67 probes for drains, tanks and wet cavities.
  • Accessories. Hook, magnet and mirror tips for retrieving objects and looking sideways.

Common uses

Task What the borescope shows
Wall cavity after a thermal or moisture anomaly Whether insulation is missing, wet or moldy; whether there is a leak
Ductwork Blockages, disconnected joints, dust, pests
Drains and downpipes Blockage location, root intrusion, cracked pipe
Behind appliances and kitchen units Leaks, pest activity, cable condition
Engine cylinders and intake Carbon build-up, scoring, valve condition
Chimneys and flues Soot, blockages, liner damage
Under floors and in crawl spaces Damp, rot, pest damage without full access
Retrieving dropped objects With hook or magnet attachment

Using it well

  1. Drill or use an existing hole in an inconspicuous place: behind a skirting, inside a cupboard, at an outlet with the power off.
  2. Bend a semi-rigid probe into a gentle curve before inserting so the camera looks along the cavity rather than at the far wall.
  3. Turn the light down for close objects, up for distance.
  4. Capture stills and video; a report with the image is worth more than a description.
  5. Note orientation: it is easy to lose track of up and down inside a wall.

Borescope versus the other tools

A thermal camera surveys a whole room in minutes and finds candidates; a moisture meter confirms water; a borescope shows what is there. The sequence is find, confirm, look. See thermal camera vs borescope and can a moisture meter detect mold. Inspection tools are covered in the thermal and inspection category.

Teslong Articulating Borescope for Mechanic Automotive HVAC Wall Inspection

Teslong Articulating Borescope for Mechanic Automotive HVAC Wall Inspection

View on Amazon
Endoscope Camera with Light, 1920P HD Borescope Tools(16.5FT)

Endoscope Camera with Light, 1920P HD Borescope Tools(16.5FT)

View on Amazon

Products shown because their documented specifications fit this guide. Price and availability are on Amazon and can change.

Frequently Asked Questions

What is the difference between a borescope and an endoscope?

Same instrument, different markets. Endoscope is the medical and consumer term; borescope is the industrial one. Inspection camera covers both.

What probe diameter do I need?

5 to 8 mm fits most inspection holes, drains and engine ports. 3.9 mm or smaller fits spark plug holes and tight cavities but has lower image quality.

Why is the image blurry close up?

Most probes have a fixed focus optimized for 30 to 100 mm. Closer than that is out of focus; dual-lens and adjustable-focus models address it.

Affiliate disclosure: Akermin earns a commission from qualifying Amazon purchases made through links on this page. Our editorial picks are based on documented specifications and owner feedback, not commissions.