Size: Height 6cm, inner diameter 5cm. which is suitable for all ball heads of the trailer hitches with a maximum diameter of 50 mm. Adapts perfectly to the shape of your trailer coupling and has hardly any room for maneuver. Function: The trailer hook of the vehicle is protected to prevent corrosion or damage to the hook as well as accidental greasing of the clothes. The tow ball protector can also be used as a small bumper when parking, so you can wash your car safely. High-quality material: the trailer hitch ball cover is made of high-quality plastics, is waterproof, moisture-resistant, tear-resistant, wear-resistant and corrosion-resistant, strong and durable. Easy installation: no other tools are required. Simply slide in, easy to install and remove. The truck ball protection cover with fixed ring can prevent loss. Wide range of applications: this trailer ball cap is suitable for all conventional tow bars, trucks, caravans, container trucks, trailers, cars, ships, to protect your trailer from dust, rust, road salt and water.