Adjustable Led Dog Collar: The Led dog collar have two size for choose M(32 - 38 cm /12.60 -19.35 inch), L(37 - 51 cm / 14.96 - 20.47 inch) Battery Charge: LIGHTWEIGHT, STURDY & DURABLE MATERIALS - The Led dog collar have one coin battery, when used out can be replaceable. 5 Setting Collar: with one press of a button, go from on, steady illumination, flash, slow flash or off. Power button isn't exposed so no need to worry about busy paws turning on the collar! Battery Replace available: It is easily to replace batteries. You can open the battery cover, remove the battery and replace the new battery. Quality Ensurance: Each of the led dog collar will be double checked before send to customer. so just enjoy the fun of running with your dogs.