One size - about 10" - 12" internal diameter. 100% cotton fabric with a quick clip lobster style clasp. Just who doesn't wanna match their puppers out on walk? Just grab your house key/car key and hook to the clasp, loop the wristlet round your wrist and off you go on your walkies! Also handy to have just for yourself, quick run to the shops with your phone and keys if you feel like flying light!