In response to cat owners' concerns....The Safe Cat buckle is designed to release when a cat's collar gets caught- allowing it to slip free. Keep your cat safe with a Safe Cat Breakaway Collar. The Safe Cat¨ Breakaway collar is made of no-snag material and is also adjustable from 8" to 12". Do not use with lead or tie-out. Cannot be used with collar keys for most electronic or magnetic doors (will work with Staywell 980 Silver Mouse magnetic keys - 980 keys included with all newly purchased doors).