SpecificationItem: Dog LED Flashing CollarMaterial: nylon, fiber opticWidth: about 2.5 cmLength: S (35-43 cm) M (40-48 cm) L (45-52 cm) XL (52-60 cm)Package includes:1 wash collar and 1 USB cable Characteristic:1, flashing mode: long light, flash, slow flash, close (through switch control).2 New style, rechargeable by USB, without battery.3, suitable for a dark environment or walking at night, outside and pet movement through the bright fiber optic light, can be warning, it is also modern and individual.