The best flea collars are also waterproof and feature a quick release mechanism, which is useful for curious kitties who often get themselves in tight spots. (pesthacks.com)
Open it up so curious kitties can hop into it if they want to, and reward them with praise and / or kibble for doing so. (bluecrosspethospital.net)
Bowser is a very curious kitty and loves to get into things that he knows he shouldn't - but we love him so much anyway! (foxvalleypets.org)