One size fits all flea & tick collar for dogs. Kills adult fleas and prevents new flea infestations. This collar provides continuous flea and tick control for up to 6 months. Designed to fit dogs at any size that are 12 weeks of age and older. This durable, water resistant collar can last up to 6 months. It doesn't lose effectiveness against fleas and ticks even if it gets wet. Simply slide the collar on your dog, lock into place, and cut off excess length.