When you're facing a thermal borescope visual inspection, the first decision isn't which brand to buy. It's how much control and image quality you actually need to trust what you see. Two options bracket that decision: a tiny $4.99 USB endoscope from KERUI and a fully articulating $178.12 borescope from Ralcam. The price gap is only the beginning.
Quick Verdict
If you want a self-contained tool that steers around obstacles and locks into place, the Ralcam is the one to get. If you want a simple USB camera for Android devices and the lowest possible price, the KERUI is the smart pick. The difference between them is not just price; it is how you inspect.
Price and Features at a Glance
| Feature | KERUI USB Endoscope | Ralcam Articulating Borescope |
| Price | USD 4.99 | USD 178.12 |
| Camera Resolution | 640×480 | 1080P |
| Probe Diameter | 7mm | 6.2mm |
| Viewing Setup | USB and Android interface | LCD display |
Both cameras are waterproof and carry six LEDs, so those features won't separate them. The real difference is in how you get the image and how the probe moves.
Where the KERUI Wins
The KERUI is the take-anywhere borescope. Its 1m cable and slim probe slide into small openings, and it connects through a USB and Android interface, so if you already have an OTG cable, you're ready to look. It is the lowest-cost way to get a waterproof camera with six LEDs, which makes it an easy first tool for homeowners or occasional checks. The 640×480 picture is basic, but it will confirm whether something is stuck, leaking, or blocked. You won't mind handing this camera to a helper or keeping it in a vehicle.
Where the Ralcam Wins
The Ralcam is the articulating inspection tool. Its 4-way 360° probe bends and locks at any angle, so you can inspect around corners and hold the view without twisting the cable. The 1080P camera delivers sharper images, while the 2600mAh battery supports longer sessions. This is the kind of tool you reach for when you need to document exactly what you see inside a heat exchanger, engine housing, or wall cavity.
Product Notes
KERUI USB Endoscope Camera
This KERUI model is the fastest way to see into a tight spot without clearing a workspace. The 1m cable and 7mm probe make it practical for checking drains, ducts, or small equipment openings. An OTG cable gets you going with a phone or tablet. The main limitation is resolution: at this level, you can identify a blockage or a large gap, but you won't get the fine detail needed to inspect a hairline crack or a worn sealing surface. For a quick-look tool, that is a reasonable trade. It is also the easier tool to carry and store, making it a good backup.
Ralcam 4-Way Articulating Borescope
The Ralcam turns an inspection into a hands-free operation. Its probe bends four ways and locks at any angle, so you can look around corners and into combustion chambers without repositioning the cable. Images are sharp enough to examine a surface closely, and the built-in display means you don't have to set up an external device. The battery gives you freedom to move, and the slim probe fits through smaller passages. The tradeoff is commitment: this is a more capable setup, so you'll want to keep the battery charged and handle the articulation mechanism with care. For regular or critical thermal borescope visual inspection, that effort pays off.
Final Choice by Use Case
If you need a quick look and want to spend as little as possible, the KERUI is the one to grab. It is easy to store, easy to connect, and good enough to tell you what's behind a wall. If your work demands a controlled, articulate view and sharper images, the Ralcam is the better investment. Choose based on how often you inspect and how much detail you need.
