Quick answer: A clip on thermal imager, often called a COTI, is a small thermal unit that clamps onto the front of an analog night vision tube and lays a heat picture over the image you already see. The tube shows the ground and the detail; the thermal shows what is warm. Our Night Operators Jerry-C Pro uses a 640x512 thermal sensor at 1x, clamps onto a PVS-14 or one tube of a PVS-31, needs no calibration after install, and costs $2,949.00. If you would rather have thermal built in from day one, the ELF-FB20 fusion binocular is the all in one choice.
What is a clip on thermal for night vision?
It is a thermal imager made to sit in front of a night vision device rather than to be looked through on its own. It has no eyepiece. Instead it projects its thermal picture into the objective lens of your tube, so when you look through the night vision you see both: the amplified light picture from the tube, and warm shapes drawn on top of it.
That pairing fixes the weak spot of each technology. An image intensifier tube needs some light and can lose a person or an animal that is still, dark and tucked into brush. A thermal sees heat whether there is light or not, but shows the world as temperature, which makes it harder to read terrain, roots and ruts at your feet. Together you get the scene from the tube and the warm target from the thermal. For the bigger picture on mixing the two, see what thermal fusion is.
How does a clip on thermal mount on a PVS-14 or PVS-31?
On the Jerry-C Pro it rides on a clamp ring that closes around the objective lens of a 1x night vision tube. The steps on our product page are three:
- Slide the clamp ring over the objective lens of your PVS-14, or of one tube on your PVS-31.
- Turn the ring to set the tension, then press the lever shut.
- Slide the Jerry-C Pro onto the ring, power it on and choose a mode. There is no calibration step.
On a PVS-31 it sits on one tube: thermal in one eye, both tubes still amplifying light. The clamp ring set for our PVS-14 and PVS-31 objectives comes with every Jerry-C Pro we ship. Objective sizes differ between makers, so for night vision that is not ours, email us your model before you order.
Do you have to calibrate or line up a clip on thermal?
Not with an optical overlay design like the Jerry-C Pro. The thermal picture is projected optically into the tube's objective, so once the clamp is closed and the unit is on, the heat lines up with the tube image. There is one limit worth knowing: very close targets line up less cleanly. On the Jerry-C Pro the overlay lines up best on targets past about 30 m, and under 10 m it is not meant to be used.
What do you actually see through a clip on thermal?
That depends on the mode. The Jerry-C Pro has two, plus an option that works with either:
- Highlight. The warm target is filled in with thermal over your tube image. Turn the threshold down and only the hottest things stay lit, so a person or an animal pops while warm rocks and walls drop away.
- Outline. Only the edges of the warm target are drawn, in three line weights. Your tube picture stays clean and the heat shows as a sharp silhouette.
- Breathing. Either mode can pulse on and off at a speed you set, so the overlay never hides detail in the tube for long.
The threshold adjusts from 100 down to 10 percent. Reading what the heat shapes mean (animal, person, engine, sun warmed rock) is a skill of its own, covered in reading thermal signatures.
How wide is the view under the thermal?
A clip on thermal sits on top of your goggle's own view, so the goggle decides how wide that view is. Here is the same hallway at night through a standard tube, a PRO tube and a GPNVG-18.
These pictures show field of view only. The blue tint is not the tube colour: our tubes are white phosphor and show the night in black and white.
Which clip on thermal specs matter?
| Spec | Jerry-C Pro | Why it matters |
|---|---|---|
| Thermal sensor | 640x512, 12 micron, uncooled | More pixels means a sharper heat outline at distance |
| Magnification | 1x | Must match a 1x tube or the overlay will not line up |
| Overlay field of view | 35 x 30 degrees | The area of your view that gets heat drawn on it |
| Lens | F/1.0 | A fast lens lets more heat energy reach the sensor |
| Recognition distance | 275 m on a 1.7 x 0.5 m target (manufacturer test figure) | A lab figure, useful to compare units, not a promise for every night |
| Power | One CR123A (about 3 hours) or the included battery pack (about 10 hours), at 22 C | Cold shortens both, as with any lithium cell |
| Weight | About 90 g with battery | Light enough that the front of the helmet barely changes |
| Water | Rated to 1.5 m for 30 minutes | Rain and a dunking are fine |
Two specs are easy to get wrong. First, magnification: a clip on made for night vision must be 1x, the same as the tube, or the warm shapes land in the wrong place. Second, sensor resolution: if sensor sizes are new to you, 12 micron vs 17 micron thermal and sensor vs display resolution explain what the numbers mean.
Clip on thermal or an all in one fusion binocular?
Both lay heat over a tube image. The difference is whether the thermal is a part you add or a part of the goggle.
| Jerry-C Pro clip on | PVS-31 PRO + Jerry-C Pro kit | ELF-FB20 fusion binocular | |
|---|---|---|---|
| Price | $2,949.00 | from $6,548.95 | from $8,299.95 |
| Thermal | 640x512, on the tube you own | 640x512 on one tube | 640x512 built in, fused into the view |
| Night vision view | Whatever your tube gives | 50 degrees per tube | 40 degrees per tube |
| Move the thermal | Yes, to another PVS-14 or PVS-31 | Yes | No, it is part of the goggle |
| Pick it if | You already own analog night vision | You want two eye night vision and thermal you can move | You want both eyes and thermal in one sealed unit |
The ELF-FB20 is a dual tube Gen 2+ binocular with a 640 x 512 thermal sensor built into the bridge. Its thermal picture is shown on an OLED and blended into the view with under 30 ms of delay. It runs about 8 hours with thermal on and about 80 hours as night vision only, on one battery pack that takes two 18650 cells. It ships to the USA and Canada only and is built to order, about 5 to 7 weeks.
What can a clip on thermal not do?
It is honest to list the limits before you spend this much:
- It is not night vision. It reads heat, not light. Without a tube behind it you see nothing, because it has no eyepiece of its own.
- It does not zoom. It is 1x by design so it lines up with a 1x tube.
- It does not see through glass. Window glass blocks thermal. More on that in what thermal cannot do.
- Close targets line up less cleanly. Past about 30 m is best; under 10 m is not what it is for.
If you want a thermal you can hold and scan with on its own, a standalone monocular such as our PREDATOR thermal monocular is the simpler buy.
Who should buy a clip on thermal?
You, if you already run a PVS-14 or PVS-31 and keep missing the animal lying still in the brush, the person standing in a tree line, or the hog behind the fence post. The tube finds the shape; the clip on tells you it is warm. Not you, if you do not own analog night vision yet: start with a PVS-14 kit and add heat later, or buy the two together. On our site the Jerry-C Pro saves $150 in a kit with any PVS-14 and $200 with any PVS-31 PRO, and the same saving comes off in the cart if you add it on the PVS-14 or PVS-31 PRO page. Our older guide is a thermal worth it if you already own night vision helps with that decision.
Our pick: already own a PVS-14 or PVS-31? The Jerry-C Pro COTI clip-on thermal at $2,949.00 adds a 640x512 heat overlay to the goggle you have, with the matched clamp ring, a wireless remote and a battery pack in the box. Starting from scratch and want it all in one? Look at the ELF-FB20 fusion binocular from $8,299.95.
Common questions about clip on thermal
What does COTI stand for?
Clip On Thermal Imager. It is a thermal unit that clamps onto the front of a night vision device and lays heat over the tube image.
Can I look through a clip on thermal by itself?
No. A clip on thermal for night vision has no eyepiece. It projects its picture into the night vision tube, so you need the tube behind it to see anything.
Does the Jerry-C Pro fit my Night Operators PVS-14?
Yes, with the clamp ring set that ships with every Jerry-C Pro from us. It is set up for our PVS-14 and PVS-31 objectives.
Does it work on a dual tube PVS-31?
Yes, on one of the two tubes. You keep both tubes for light and add heat to one eye.
Will it fit night vision from other brands?
The clamp is built for the PVS-14 and PVS-31 objective family. Objective sizes differ between makers, so email info@nightoperators.com with your model before ordering for anything that is not ours.
Do I need to calibrate it to my tube?
No. The overlay is optical, so the heat lines up with the tube image once the clamp is closed and the unit is on. It lines up best on targets past about 30 m.
How long does the battery last?
About 3 hours on one CR123A in the unit and about 10 hours on the external battery pack, at 22 C. Cold shortens both.
What is the difference between Highlight and Outline?
Highlight fills warm targets with thermal so they jump out. Outline draws only their edges, so the night vision detail on and around them stays clear.
Is a clip on thermal better than a fusion binocular?
Neither is better for everyone. A clip on suits buyers who already own analog night vision and want thermal they can move between devices. A fusion binocular suits buyers who want two eye night vision and thermal in one sealed unit from day one.
How much does the Jerry-C Pro cost?
$2,949.00 direct. In a kit with a PVS-14, $150 comes off; with a PVS-31 PRO, $200 comes off.
Already own a PVS-14 or PVS-31? Add heat to the goggle you have. The Jerry-C Pro ships with the matched clamp ring, a wireless remote and a battery pack. Jerry-C Pro, $2,949.00.