Model PB-06 Light bulb Main light: 6*LED Tail light: 8*LED red light Product size/net weight Front: 7*6*3CM Back: 9.2*5*3CM 156G Box size/gross weight Material ABS Switch Press the switch Battery Built-in 2600mAh 18650 battery Charging time/battery life Charging time: 5H Battery life: 5H Charging method Type-C USB charging Gear position 2nd mode: 6*LED strong light - 6*LED weak light When the current light is on, the tail light flashes red in a breathing pattern using 8 LEDs Zoom mode Fixed focus Waterproof rating IPX4 Lumen/Range 300-400LM 50- Features Triangular reflective strap: No need to worry about it falling off during running. The battery compartment on the back of the backpack features an LED warning light. The front light can be adjusted 45 degrees up and down Indicator light 4 LED power indicators: 25%-50%-75%-100% The LED flashes blue when charging Color specifications Standard default black strap, customizable fluorescent green strap The package contains Running light + data cable + leather box packaging Model PB-09 Light bulb Main light: T6+12*COB white light Tail light: 8*LED red light Product size/net weight Front: 7*6*3CM Back: 9.2*5*3CM 153G Box size/gross weight Material ABS Switch Press the switch Battery Built-in 2600mAh 18650 battery Charging time/battery life Charging time: 5H Battery life: 5H Charging method Type-C USB charging Gear position Main light (4 modes): T6 strong light - 12*COB strong light - T6+12*COB simultaneous lighting - T6 SOS Double-click the tail light to turn it on/off: 8*LED red light breathes and flashes Zoom mode Fixed focus Waterproof rating IPX4 Lumen/Range 400-500LM 50- 100m Features Triangular reflective strap: No need to worry about it falling off during running. The battery compartment on the back of the backpack features an LED warning light. The front light can be adjusted 45 degrees up and down Indicator light 4 LED power indicators: 25%-50%-75%-100% The LED flashes blue when charging Color specifications Standard default black strap, customizable fluorescent green strap The package contains Running light + data cable + leather box packaging 1. Check the battery: Make sure the battery has power and insert it into the flashlight in the correct direction. Do not use batteries of different brands, and do not mix old and new batteries. 2. Determine the fault: Unscrew the back part to expose the negative terminal of the battery, then use a metal piece such as a key or tweezers to connect the negative terminal of the battery to the exposed, unoxidized part of the flashlight body, and see if it lights up.If possible, it's a problem with the flashlight switch.Please follow step 3 for inspection. If it still doesn't light up, please check the solder joints between the circuit compartment and the circuit board for any open or loose welds. If there are any, please re-solder them to resolve the issue. 3. Check the tail cover switch: Unscrew the end of the flashlight, and you will see that the outer ring of the switch cap has a switch pressure ring with two concave points. Use scissors.. Use tweezers with good rigidity to insert into the two recessed points and turn them clockwise to check whether the switch pressure ring is loose. Ensure that the switch pressure ring is tightly pressed against the switch and there should be no looseness. 4. Check for poor contact: When the flashlight does not light up or has poor contact, check whether the lamp head is loose, inspect the tail cap to ensure the switch is tightly screwed and well-connected, and ensure that the copper post of the tail cap is in good contact with the metal ring of the tail cap. 5. Other issues: If the above methods still cannot resolve the issue, please contact our customer service, and we will assist you in resolving the problem.