Love the colors & the collars seem to work with birds. The bell helps our timid cat keep track of our bully cat. I’ve taken the bell off the timid cat’s collar, will see if that impacts warning the birds. Using brightest collar(s) on long haired cat as the long fur diminishes collar visibility. Initially the cat lost 2 collars. Recently found one with holes in the material snagged in brush (we have a large, naturalized garden). The collar did not break away. No idea how long the cat struggled to get it off. Also the long haired cat scratches a lot, her fur seems to get snagged on the breakaway collar’s buckle etc. I have to rotate it in the colorful sleeve to alleviate the problem. But, overall, fewer birds are caught.