| MODEL | DT-NH921 | DT-NH931 |
| IIT | Gen2+ | Gen3 |
| Magnification | 1X | 1X |
| Resolution | 45-57 | 51-57 |
| Photocathode type | S25 | GaAs |
| S/N(db) | 15-21 | 18-25 |
| Luminous sensitivity(μa-lm) | 450-500 | 500-600 |
| MTTF（hrs） | 10,000 | 10,000 |
| FOV(deg) | 42+/-3 | 42+/-3 |
| Detection distance(m) | 180-220 | 250-300 |
| Adjustable range of eye distance | 65+/-5 | 65+/-5 |
| Diopter(deg) | +5/-5 | +5/-5 |
| Lens system | F1.2, 25mm | F1.2, 25mm |
| Coating | Multilayer broadband coating | Multilayer broadband coating |
| Range of focus | 0.25--∞ | 0.25--∞ |
| Auto anti strong light | High Sensitivity, Ultra Fast, Broadband Detection | High Sensitivity, Ultra Fast, Broadband Detection |
| rollover detection | Solid non-contact automatic detection | Solid non-contact automatic detection |
| Dimensions (mm) (without eye mask) | 130x130x69 | 130x130x69 |
| material | Aviation aluminum | Aviation aluminum |
| Weight (g) | 393 | 393 |
| Power supply (volt) | 2.6-4.2V | 2.6-4.2V |
| Battery type (V) | AA(2) | AA(2) |
| Wavelength of infrared auxiliary light source (nm) | 850 | 850 |
| Wavelength of red-explode lamp source (nm) | 808 | 808 |
| Video capture power supply (optional) | External power supply 5V 1W | External power supply 5V 1W |
| Video resolution (optional) | Video 1Vp-p SVGA | Video 1Vp-p SVGA |
| Battery life (hours) | 80(W/O IR) 40(W/IR) | 80(W/O IR) 40(W/IR) |
| Operating Temperature (C | -40/+50 | -40/+50 |
| Relative humidity | 5%-98% | 5%-98% |
| Environment rating | IP65（IP67 Optional） | IP65（IP67 Optional） |
As shown in Figure ②, rotate the work switch one gear in the clockwise direction, the knob indicates to the "ON" position, and the system is turned on. At this time, the system starts to work and the image tube lights up. (Turn clockwise in turn: ON/IR/AUTO). The IR turns on the infrared light, the AUTO enters the automatic mode. 
Choose a target with moderate ambient brightness and adjust the eyepieces without opening the objective lens cover. As shown in Figure ③, turn the eyepiece handwheel clockwise or counterclockwise to match the vision of the human eye. When the clearest target image can be observed through the eyepiece, the eyepiece adjustment is complete. When different users use it, they need to readjust according to their own vision. Push the eyepiece toward the middle or pull the eyepiece outward to change the distance of the eyepiece. 
The purpose of objective lens adjustment to see clearly at different distances. Before adjusting the objective lens,Please adjust the eyepieces first according to the aforementioned method. When adjusting the objective lens, please select a darker environment. As shown in Figure ④, open the objective lens cover, aim at the target, and turn the objective lens focusing handwheel clockwise or counterclockwise until the clearest environment image is seen, and the objective lens adjustment is completed. When observing targets at different distances, the objective lens needs to be adjusted again according to the aforementioned method. This product has four working switches, there are four modes in total, in addition to shutdown (OFF), there are also three working modes such as "ON", "IR", and "AT", which correspond to the normal working mode and the infrared mode , Auto mode, etc., as shown in Figure ..When the ambient illuminance is very low (full black environment), and the night vision device cannot observe a clear image, you can turn the work switch clockwise to another gear. the system enters the "IR" mode. At this time, the built-in infrared auxiliary lighting of the product is turned on to ensure normal use in a completely dark environment. Note: In the infrared mode, if you encounter similar equipment, it is easy to expose the target.The automatic mode is different from the "IR" mode, and the automatic mode starts the environment detection sensor. It can detect environmental illuminance in real time and work with reference to illumination control system. Under extremely low or extremely dark environment, The system will automatically turn on infrared auxiliary lighting, and when the environmental illumination can meet normal observation, The system automatically closes "IR", and when the ambient illumination reaches 40-100Lux, The whole system is automatically shut down to protect the photosensitive core components from damage by strong light.
In order to ensure the user's comfort when using this system, the helmet pendant system is designed with a perfect fine-tuning structure to meet the needs of different users. Up and down adjustment: Loosen the height locking knob of the helmet pendant counterclockwise, slide this knob up and down, adjust the product eyepiece to the most suitable height for observation, and turn the height locking knob of the helmet pendant clockwise to lock the height. As shown in Figure ⑦ the red icon.Left and right adjustment: Use your fingers to press the left and right adjustment buttons of the helmet pendant to slide the night vision components horizontally. When adjusted to the most suitable position, release the left and right adjustment buttons of the helmet pendant, and the night vision components will lock this Position, complete left and right horizontal adjustment. As shown in green in Figure ⑦. Front and back adjustment: When you need to adjust the distance between the night vision goggles and the human eye, first turn the equipment locking knob of the helmet pendant counterclockwise, and then slide the night vision goggles back and forth. After adjusting to the proper position, turn the equipment clockwise to lock Turn the knob, lock the device, and complete the front and back adjustment, as shown in blue in Figure ⑦.
After the product has been worn, in the actual use process, if the night vision goggles are not used temporarily, the night vision goggles can be flipped and placed on the helmet, so that it will not affect the current sight line, and it is convenient to use at any time. When you need to observe with the naked eye, press and hold the flip button of the helmet pendant to flip the night vision component upwards. When the angle reaches 170 degrees, release the flip button of the helmet pendant, and the system will automatically lock the flip state; you need to put down the night vision component When observing, you also need to press the flip button of the helmet pendant first, and the night vision component will automatically turn back to the working position and lock the working position. When the night vision component is turned over to the helmet, the system night vision device will be automatically turned off. When it is turned back to the working position, the night vision device system will automatically turn on and work normally. As shown in Figure ⑧.1.No power A. please checks whether the battery is loaded. B. checks whether there is electricity in the battery. C. confirms that the ambient light is not too strong. 2. Target Image is not clear. A. check the eyepiece, whether the objective lens is dirty. B. Check the lens cover open or not ?if at night time C. confirm whether the eyepiece is properly adjusted (refer to eyepiece adjustment operation). D. Confirm the focusing of the objective lens ,whether finished adjusted.r (referring objective lens focusing operation). E. confirms whether infrared light is enabled when the environments all back. 3. Automatic detection not working A. automatic mode, when glare automatic protection does not work. Please check if the environmental testing department is blocked. B. flip, the night vision system does not automatically turn off or install on the helmet. When the system is in normal observation position, the system cannot start normally. Please check the position of the helmet mount is fixed with the product. (reference headwear installation). 1. Anti-strong light The night vision system is designed with automatic anti-glare device. It will automatically protect when encountering strong light. Although the strong light protection function can maximize the protection of the product from damage when exposed to strong light, but repeated strong light irradiation will also accumulate damage. So please do not put products in strong light environment for a long time or many times. So as not to cause permanent damage to the product.。 2. Moisture-proof The night vision product design has waterproof function, its waterproof ability up to IP67 (optional), but long-term humid environment will also slowly erode the product, causing damage to the product. So please store the product in a dry environment. 3. Use and preservation This product is a high precision photoelectric product. Please operate strictly according to the instructions. Please remove the battery when it is not used for a long time. Keep the product in a dry, ventilated and cool environment, and pay attention to shading, dust-proof and impact prevention. 4. Do not disassemble and repair the product during use or when it is damaged by improper use. Please contact the distributor directly.
First, turn the knob on the helmet mount device to theend of the clock counter clockwise. Then use the universal fixture of the night vision instrument to one end ofthe eyepiece to the equipment slot of the helmet hanging device. Press the device button on the helmet mount vigorously. At the same time, the night vision instrument is pushed along the equipment slot. Until the button of center is moved to the middle at the universal fixture. At this time, release the anti button, turn the equipment locking knob clockwise and lock the equipment. As shown in Fig. 5.After installing the night vision instrument, Fasten the pendant of helmet mount to the general equipment slot of the soft helmet. Then press the lock button of the Helmet Pendant. At the same time, the components of the night vision instrument and Helmet Pendant are rotated counterclockwise. When the helmet mount connector is completely attached to the universal equipment slot of the soft helmet, Loosen the lock button of the Helmet Pendant and lock the product components on the soft helmet. As shown in Fig. 6.