DLAND LED Pet Dog Collar, Led USB Rechargeable Pet Safety Collar Visible 1640ft Waterproof Light up Length Adjustable Flashing Collar(Blue) Flashing Mode:Quickly Flashing / Slowly Flashing / Lighten up(approx. 100 hours flashing light,approx. 50 hours Lighten up),and size individually adaptable by simple cutting. LED light visible approx. 500meters(1640 ft) depending on the charge status of the battery and the surrounding conditions. No need batteries ,and can be recharged by means of USB cable with any other daily use device,e.g computer that has USB port or smartphone Chargers. Fully weather-resistant,: waterproof function, can be used in raining days. good for all conditions, Adjustable & Comfy for your dog. Safety dog collar: In low light conditions, which can help you keep your dogs safe.