Light up dog collar available in three adjustable sizes. Please leave enough space between dogs neck and collar when measuring the neck circumference to give them enough room to breathe, then choose the size that fits the measured length. Small Dog Collar: 30.5cm 40.6cm / 12 16 inches Dog Collar Medium: 40.6cm 48.3cm / 16 19" inches Large Dog Collar: 48.3cm 59.9cm / 19 23.6 inches SAFETY IS OUR PRIORITY: AVOID TRAFFIC ACCIDENT: LeZampa Dog Light up Collar provides high visibility upto 500meters, so traffic vehicles can spot your dog from far keeping them safe from collisions. ANTI-LOST & HIGH VISIBILITY AT NIGHT: If your dog is wearing our unique flashing dog collars for dark, you will be able to spot it easily when they are playing at the beach, park, bushes or during other outdoor activities at night. ELEGANT RANGE OF 4 COLORS PREMIUM MATERIAL & WEATHERPROOF: High quality PVC Leather and Nylon webbing make our illuminated dog collars more durable. Our light up collar is suitable for all weather conditions, i.e. rainy days, water splashes etc. ANTI LOST & AVOID TRAFFIC ACCIDENT AT NIGHT: Flashing dog collar helps spot your dog on snow-covered streets, in the forest or on the driveway at dusk. Our dog collar light helps vehicles on the road spot your dog enhancing your dogs safety at night. 3 LIGHTING MODES: You can set the LED dog collar light in three different flashing modes, i.e. Quick Blink, Slow Blink & Steady Light with ON/OFF button. 3 ADJUSTABLE SIZES: Our dog light up collar available in 3 sizes. Small size range is 30.5cm 40.6cm / 12 16 (inches). NOTE: Adjustment is not limited to black nylon adjustment area, but collar can be shortened up to PVC leather area to get desired size as shown in video. USB RECHARGEABLE: Easily rechargeable USB battery (150mAH) lasts more than 8 hours (charging cable included). NOTE: Please charge battery for at least 2 hours before first use.