The Tekonsha 5603 Grease Seal features an Outside Dimension of 1.987 and an Interior Dimension of 1.5. Intelligent trailer braking is the key to the success of the Tekonsha product line. What began as a manufacturer of RV stairs and steps in 1964, Tekonsha has evolved to become a trusted name in towing safety. The core product line consists of brake controllers, electrical wiring and trailer brakes. The Tekonsha line has been trusted by professional towers and weekend warriors for worry-free travel.