Your thrill sniffer will be visible to cars and other pedestrians wearing this alcott Visibility Dog Vest that features reflective trim and dog graphic. Use during both daytime and nighttime adventures for improved visibility. The vest is lightweight, fully adjustable and ideal for daily use. The Small alcott Visibility Dog Vest has the following sizing/measurements: Length (10.5"), Chest (13" to 17") and Waist (18" to 24"). The Medium alcott Visibility Dog Vest has the following sizing/measurements: Length (14"), Chest (18" to 24") and Waist (24" to 28"). The Large alcott Visibility Dog Vest has the following sizing/measurements: Length (18"), Chest (24" to 30") and Waist (24" to 32"). They are available in two neon colors and also have matching nylon collars, nylon leashes, retractable leashes, harnesses and bandanas available from alcott!