Come and see our amazing products. The LED pet dog collar is made of nylon. Each one has 2 pcs button batteries. Battery can be used for 60-80 hours, normally for 2-3 months. And the battery is replaceable. The product is suitable for dark environment or walking the dog at night,outdoor and pet movement. Through the bright fiber optic light, it's great for a walk in the dark or even during the day with its bright, easy to spot colors.This item has four size,if you interest, feel free to contact. Pls confirm with us about the packing info, stock color and exact production time before placing your order.