They stink, look dirty and cause skin irritations.
Our collars are stink proof, too. Made of medical grade thermo-elastomer, C4 collars are non-porous which makes them waterproof, stain resistant, hypoallergenic, and easily washable.Sprinkles Dog Collar With Silver Buckle - X-Large Most Collars stay wet and are like sponges for dirt, grime, and bacteria. Not C4.