Peppermint Flea & Tick Collar repels bugs and is an added layer of protection against fleas and ticks for up to 4 months, mosquitoes up to 1 month. Use with Flea & Tick Pets + Home spray to protect your pet. Active issue? Collar doesn't kill bugs. Use Flea & Tick sprays for pets, home and yard as directed 

Small/Medium Dogs: Fits necks 9.5"–21".
Large Dogs: Fits necks 13.5"–26".

Looking for our One Size Fits All Dog Collar? That size is now listed as Small/Medium.