These are used to identify puppies Soft collars with easy snap feature Would unsnap incase of emergency The different colours can also make puppy/kitten selection Easy to keep track of each puppy or cat weight gain their develop, to check food consumption in feeding time, and management health and behaviours. Make sure to check the collar under the daily wear, is too loose or too tight (about 2 refers to the space around) 100% Brand New and High Quality Type:Identification Collars Material:Nylon+Double Velvet Color:15 Colors QTY:15PCS Size:10*200MM/10*300MM/10*350MM Package Include:15pcs Puppy ID Collars Size: S- 10*200MM long for newborn to 2 weeks of pet use M – 10*300MM long for 2 to 4 weeks pet use L- 10*350MM long for 4 to 6 weeks pet use Note: 1.Due to the light and monitors effect, colors may have lightly difference. 2.Please allow slightly size errors due to manual measurement. Thank you for your understand! 3.1mm=0.039”.