DGYAO&reg; Glowing Fiber Optics Lighted Adjustable Flashing Safety Nylon Dog Cat Pet Collar For Night Walks LED light glows and flashes in darkness. Helps to keep you and your dog & other pets safe during walking. Provide safety for your dogs and pets while it's out alone at night. Easy to use: simply pushing the control button makes the light ON/FLASH/OFF. Please check the size:M,L,XL.before you choose it.