Seresto Cat Collars kill and repels fleas and ticks for 8 continuous months in one easy-to-use, non-greasy, odorless collar.
The Seresto Formula quickly kills fleas within 24 hours of initial application.
Re-infesting fleas are killed within 2 hours. This collar also prevents against tick infestations within 48 hours after application as well as kills and repels re-infesting ticks in as quickly as 6 hours!

Active Ingredients: Flumethrin & Imadacloprid.

Seresto collars are safe for cats over 10 weeks of age.