Quick answer: a COTI is a clip on thermal imager that draws heat on top of your night vision picture, and how it draws it is its mode. Our Night Operators Jerry-C Pro ($2,949) has two: Highlight fills a warm target in, Outline traces only its edges. Breathing pulses either one on and off, and a compass heading runs across the top. See the Jerry-C Pro, from $2,949.
Most clip on thermal pages show one glowing silhouette and stop there. In the field, what you actually work with is the mode, the threshold and a handful of settings that decide how much heat lands on top of your tube picture. This guide goes through every mode and setting on the Jerry-C Pro, with real frames from Bon's own footage beside our illustrations, so you know what you will see before you buy.
What modes does a clip on thermal have?
The Jerry-C Pro has two image modes and one option that works with either. There are no colour palettes: the heat is drawn in the overlay colour on top of your tube picture, and the tube decides the colour of everything else.
| Mode or setting | What it draws | Best for |
|---|---|---|
| Highlight | Warm targets filled in, brightest where warmest | Finding a warm body fast |
| Outline | Only the edges of warm targets, in 3 line weights | Keeping the tube picture clean around the target |
| Breathing | Highlight or Outline pulsing on and off | Long watches, so the overlay never hides detail for long |
| Threshold | How warm something must be to be drawn, 100 to 10 percent | Dropping warm rocks and walls, keeping people and animals |
| Compass heading | A curved heading strip across the top of the view | Knowing which way you face without a second device |
What does Highlight mode look like?
In Highlight mode the warm target is filled in with thermal over your tube image. In real use the fill is not a flat glow. It is graded by warmth: brightest on the face, neck, hands and core of the body, dimmer over cooler clothing, darkest at cold shoes. You can still read folds and shape inside the glow, with a soft bright rim at the edge, while the background stays plain night vision.
The picture at the top of this post is a real frame from Bon's video through his PVS-14 STANDARD with the Jerry-C Pro on, in Highlight mode. Below is our illustration of the same idea.
Turn the threshold down and only the hottest things stay lit. That is the trick that makes Highlight useful in the field: a person or an animal pops while sun warmed rocks, walls and road edges drop away. Turn it up and more of the scene lights up, which helps when targets are cool, such as a distant animal on a cold night.
What does Outline mode look like?
In Outline mode only the edges of warm things are drawn, as thin bright lines, and you can choose between three line weights. Your tube picture stays clean, and the heat shows as a sharp silhouette around the shape. That makes Outline the mode for reading the ground around a target: you see the animal's shape and everything around it in full tube detail.
The threshold matters even more in Outline. At high sensitivity a lot of edges light up: the person, tree trunks, warm curb edges, a lamp. The scene gets busy. Turn it down and only the person and the strongest edges stay. In the frame above, the threshold is low enough that the person on the path stands out from the trees around them.
What is Breathing mode for?
Breathing makes either mode pulse: the overlay fades on and off at a speed you set. It sounds like a gimmick until you sit through a long watch. With Breathing on, the heat reminds you where to look on each pulse, and between pulses you see the full tube picture with nothing on top. Nothing stays hidden under the overlay for long. Set the speed with the plus and minus button.
What is the compass HUD?
Across the top of the view the Jerry-C Pro draws a long, shallow, curved heading strip with compass marks and labels on it, and your heading in larger digits under the middle. In the real frames above you can read it: 325 degrees in one, 347 in the other. It is always there while the unit is on, so you always know which way you are facing without reaching for a phone or a second device. When you change a setting such as brightness, a short bar appears down the right edge while you adjust it and then gets out of the way.
How do you switch modes and settings?
Three buttons do everything, and the wireless 2.4G remote carries the same three, so you can change modes with the unit on your helmet without reaching for it.
| Button | Short press | Long press |
|---|---|---|
| PWR | Shutter calibration (refreshes the thermal picture) or a custom action | On and off |
| M | Switch between Highlight and Outline | Open the menu |
| + / - | Quick adjust: brightness, threshold, Breathing speed |
What do the automatic settings do?
- Auto brightness sets the overlay brightness for you, so it does not glare on a dark night or wash out on a bright one.
- Auto standby puts the unit to sleep after a minute of sitting still, and switches it off after ten.
- Sleep on flip up puts it to sleep when you flip the goggle up, and switches it off after ten minutes up. Flip down and it is back.
- Dormancy turns the thermal off and keeps only the compass, for when you want a heading without any heat on the picture.
All of these stretch the battery. On one CR123A the Jerry-C Pro runs about 3 hours, and about 10 hours on the external battery pack, both at 22 C. Use CR123A 3V lithium cells only; never use 16340 rechargeables, which run at 3.7V.
Why are there no colour palettes?
Handheld thermals offer palettes such as white hot, black hot and colour scales, because their screen shows nothing but heat. A clip on thermal works differently. Its job is to mark warm things inside a picture your night vision tube is already drawing, so the tube sets the look of the scene and the overlay only adds the heat. That is why the Jerry-C Pro gives you ways to draw the heat (fill or outline, threshold, line weight, Breathing) instead of a list of palettes. If palettes matter to you, you probably want a handheld; read COTI vs thermal monocular.
Do the modes work at every distance?
The modes do, but the overlay has a sweet spot. The Jerry-C Pro lines up best on targets past about 30 m, and under 10 m it is not meant to be used. Close in, the heat can sit slightly off the target in the tube picture. Past 30 m the two line up, and that is where both modes are at their best. For far targets, Highlight with a higher threshold is often the easier mode to spot something in, because a small warm shape filled in is easier to see than a few thin lines.
Which mode should you use when?
A simple way to start: Highlight with a low threshold to find things, Outline to watch them and read the ground around them, Breathing on for long sits. Reading what the shapes mean, whether it is an animal, a person, an engine or a sun warmed rock, is a skill of its own; our guide on reading thermal signatures is the place to learn it. And weather changes everything about thermal contrast; see thermal in rain, fog and snow.
The modes look the same whichever goggle the Jerry-C Pro is on. For fit and mounting, read COTI for PVS-14 or COTI on a PVS-31 or dual tube. For the basics of what a clip on thermal is, start with what is a COTI.
Frequently asked questions
What is a COTI?
A COTI is a clip on thermal imager. It clamps onto the objective lens of an analog night vision tube and draws heat on top of the tube picture, either filled in or as outlines. Our Jerry-C Pro is a 640 x 512 thermal at 1x with Highlight, Outline and Breathing modes, for $2,949.
What modes does the Jerry-C Pro have?
Two image modes: Highlight, which fills warm targets in, and Outline, which draws only their edges in three line weights. Each has a threshold from 100 to 10 percent. Breathing pulses either mode on and off. A compass heading, auto brightness, auto standby and sleep on flip up are built in.
How much is a COTI?
Our Jerry-C Pro is $2,949. The US dealer listings we compared for the same 640 x 512 class ran $3,577 to $4,475 when we read them on 22 October 2026. In a kit, $150 comes off with any of our PVS-14 monoculars and $200 with any PVS-31 PRO.
What is the most affordable COTI?
The lowest priced complete 640 x 512 clip on thermal we found was our Jerry-C Pro at $2,949, against US dealer listings of $3,577 to $4,475 read on 22 October 2026. It comes with both overlay modes, Breathing, the compass heading, a wireless remote and a battery pack.
What is the best COTI for the money?
Look for a 640 x 512 sensor at 1x, both Highlight and Outline modes with an adjustable threshold, no calibration and a remote. The Jerry-C Pro has all of that at $2,949, under the dealer listings we compared. Warranty is 3 months, up to 12 months with Operator Care.
What is the best COTI for the price?
At $2,949 the Jerry-C Pro gives you Highlight, Outline in three line weights, Breathing, a 100 to 10 percent threshold, a compass heading and a wireless remote on a 640 x 512 sensor. The 640 x 512 US dealer listings we read on 22 October 2026 started at $3,577.
One clamp ring, one heat picture laid over the night vision you already own. The Night Operators Jerry-C Pro is a 640 x 512 clip on thermal imager at 1x for the PVS-14 and the PVS-31, with a wireless remote, a battery pack and the clamp ring set in the box. Jerry-C Pro, from $2,949.