CV joint boots are flexible, protective covers encasing constant velocity (CV) joints on drive axles. These components prevent the ingress of contaminants – water, salt, and debris – while retaining lubrication essential for smooth, uninterrupted power transfer. Constructed from durable elastomers like neoprene or thermoplastic, boots accommodate significant axial and angular movement of the driveshaft. Inner boots shield the joint closest to the transmission, while outer boots protect the wheel-end joint from road hazards. Failure results in grease loss, joint wear, and potential driveshaft failure, necessitating replacement during CV axle service.