Fits all Educator 300, 400, 500 and 900 series training collar receivers, as well as Bark-less Pro model 504 High quality Biothane material provides unmatched durability and will not fray, is waterproof and odorproof, perfect for outdoors and active dogs Easy to clean Biothane collar featues a heavy-duty steel buckle and D ring for leash and ID tag will not rust Dog collar measures 3/4 inch wide x 30 inches long, strap can be trimmed to desired length for a custom fit Your complete satisfaction is our only concern; live US phone support is available