Universal Pet Flashing Ultra Bright 2 LED Reflective Dog Collar (Various Sizes) Fits neck size range: 13-3/8 to 14-1/2; Band thickness: 1-5/16 Reflects in yellow with built-in LED bulbs inside the collar On/off button for light modes; D-ring attached for leash/ID Secure plastic buckle on black elastic band Requires 1 CR2032 battery (included)