Eliteshine Super Bright Flashing Nylon LED Light Pet Dog Safety Collars (DD-WT-1, Blue) New-Generation LED collar necklace that give fantastic lights on pets neck. Three blinking modes availablefast flash, slow flash and light on With lithium 2piecs CR2016 button batteries(include) which can keep on flashing for 60-80 hours (blinking mode) and 30 hours (light on mode) With S, M, L, XL sizes available. Washable