FOR EVERYONE - The bike antenna is for beginners or professionals and fits all standard bicycles and just needs 10mm to fit (the width of a pencil). If you are just beginning to exercise with your dog this is perfect. Use a bungee line 9 ft long and we recommend the 2.8 meter Non-stop dogwear Bungee Running Line. HOW IT WORKS - Prevents the bungee line from getting tangled in your wheel or pedals. Now you can exercise without worry of dangerous tangles, mistakes and avoidable falls. WHAT IT DOES - The bike antenna is a metal extension with a very strong spring which guides your dog's line over your front tire. This means you can safely and confidently exercise your active dog. EASY TO INSTALL - Use the pictures and videos on You Tube for easy installation. Designed by World Champions for use in all bikejoring and scooterjoring events. EASY TO MAINTAIN - We are like you and love to bicycle with our dog and also alone. So we made the Bike Antenna so that with a hex wrench you can slide the antenna off for when you want to ride just by yourself. One size fits most bicycles. For questions or help call Non-stop dogwear's USA headquarters in Alaska (907) 412 2361.