Good quality, tried under running water and those are waterproof. It's smaller by 0.5cm in length, so don't be shy and size up, got a size 6 which is supposed to be 6cm in length but it's only 5.5cm Reflective, bottom is a kind of rubber, my dog can't take it off. For reference, my dog is 9.7kg and 35cm tall and 45cm long - small/ medium