The ATN ThOR-320 is an American 2x magnification thermal imaging sight. The sensors installed in forward-looking infrared cameras, as well as those of other thermal imaging cameras, use detection of infrared radiation, typically emitted from a heat source (thermal radiation), to create a "picture" assembled for video output. They can be used to help pilots and drivers pilot their vehicles at night and in fog, or to detect warm objects against a cooler background.
It is available in Battlefield 4 as a primary weapon optic, where is referred to as the FLIR (IR 2X).
— Battlelog description
The FLIR is a 2x Magnification sight featured in Battlefield 4 with an integral Range Finder and uses white-hot thermal imaging when aiming down the sight. The scope takes up the entire screen, similar to sniper rifle scopes.
It can be used for a variety of purposes, ranging from seeing enemies in foliage to dark areas on maps. Along with the IRNV, the FLIR is unable to see through the cover of Smoke Grenades, and the two IR scopes are very vulnerable to the blinding effects of the Hand Flare as well as other bright light sources, which will completely glare the screen when aiming at them with either sight.
— Battlelog Description
The FLIR (2x) is an attachment featured in Battlefield Hardline, functioning in the same exact manner as the Battlefield 4 variant.
- There is a glitch that occasionally makes the sight lack night vision, essentially making it a 2X sight without peripheral vision and only a single red dot reticle on the center. The same glitch happens with the IRNV. The glitch usually happens within the first 30 seconds after spawning.
- Also, another rare glitch happens on high-latency servers in which after aiming down the FLIR (and the player is in hip-fire mode) the entire map is rendered in black and white thermal vision (much like in ADS mode) but returns to normal after a few seconds.
- It is possible to equip the M98B sniper rifle with the 2x FLIR scope (and 1x IRNV scope) and 14x Variable Zoom. This is accomplished by equipping a standard rifle scope with 14x Variable Zoom on the M98B, and then switching the rifle scope to the 2x FLIR. While the FLIR will still render in black and white while using the 2x setting, it will not render when using the 14x Variable Zoom. This allows the player to have a close range optic, long range optic, and a range finder. This combination is not possible through any other means.
- In BF4, the FLIR sight used to be able to see through smoke. This was patched however.
- The FLIR sight had a hard time picking up soldiers wearing the DICE LA camo. This was patched on August 25, along with the UI update.