Definitely go with a break away collar. Our kitties do manage to get into the darndest places, the break aways are a safe bet. Please reconsider letting your kitty go outside. Groucho will be 5 in March and has always been an indoor guy. He's happy, active, loves to play, and spends hours sitting in the window. There are so many dangers out there... traffic, predatory animals, various assorted harmful plants & chemicals. Then there are those people who think hurting or stealing little animals for a research lab is great fun. And please don't forget to spay/neuter!!! There are some experienced, knowledgable folks right here on PT willing to answer any questions you may have about spay/neuter.