MyPaw LED Rechargeable Dog Collars Adjustable Glow in The Dark Flashing Light, Stylish Leopard Print, Great Fun, Improved Night Visibility and Safety Money Back Guarantee Adjustable / Water-Resistant 3 light settings / 72 Hour Battery Charge Rechargeable battery by plugging into any USB port Available in four sizes: Extra Small 1" wide, fits necks 11"-15" / Small 1" wide, fits necks 12"-16" / Medium 1" wide, fits necks 15"-20" / Large 1" wide, fits necks 15"-24"