Model PB-03 Light bulb 3*LED front lights + 8*LED red light tail lights Product size/net weight Front: 4.7*4.7*1.8CM Rear: 10*5.4*1.7CM 172G Box size/gross weight 12.4*10*7.5CM 226G Material ABS Switch Press the switch Battery Built-in 2000mAh polymer battery Charging time/battery life Charging time: 3-5 hours Battery life: 4-15 hours Charging method Type-C USB charging Gear position Three modes: 3*LED strong light - 3*LED weak light - 3*LED rapid flashing (the tail light's 3*LED red light mode changes along with the front light) 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 5 red LED power indicators: 20%-40%-60%-80%-100%. The battery indicator lights up when charging The package contains Running light + TYPE-C data cable + English single-sided manual + color box Model PB-05 Light bulb 5*LED front lights + 8*LED red light tail lights Product size/net weight Front: 4.6*4.6*2.2CM Rear: 10*5.4*1.7CM 174G Box size/gross weight 12.5*10*8CM 230G Material ABS Switch Press the switch Battery Built-in 2000mAh polymer battery Charging time/battery life Charging time: 3-5 hours Battery life: 4-15 hours Charging method Type-C USB charging Gear position Three modes: 5*LED strong light - 5*LED weak light - 5*LED rapid flashing (the tail light's 3*LED red light mode changes along with the front light) 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 5 red LED power indicators: 20%-40%-60%-80%-100%. The battery indicator lights up when charging The package contains Running light + TYPE-C data cable + bilingual instruction manual in Chinese and English + color box Model PB-07 Light bulb 7*LED white light + 8*LED red light Product size/net weight Head part 9*4.4*10.1cm Battery pack 11.2*7*1.8cm 171.5G Box size/gross weight 10*8.2*12.5cm 234.2G Material ABS Switch Press the switch Battery Built-in 2000mAh polymer battery Charging method Type-C USB charging Gear position Three modes: 7*LED strong light - 7*LED weak light - 7*LED rapid flashing (rear light 3*LED red light mode follows the front light) The lights change together) Zoom mode None 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 When charging, 5 red LEDs light up The package contains Running light + TYPE-C data cable + bilingual instruction manual in Chinese and English + color box 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 recesses. Use scissors or a sturdy pair of tweezers to insert into the two recesses and turn clockwise to check if the switch pressure ring is loose. Make sure 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 do not resolve the issue, please contact our customer service, and we will assist you in resolving the problem.