Feature: 1. The bearing buddies can maintain pressure on the grease inside the bearing to prevent water and dust from entering. 2. The spring‑loaded piston exerts a slight pressure of 3psi on the grease, maintaining a slight pressure between the inside of the hub and the outside environment. 3. The automatic pressure relief function prevents over filling and over pressurization, dependable to use. 4. Help you avoid serious mechanical problems and provide long‑lasting and economical solutions for bearing protection. 5. Easy to install, simple and fast in filling them with a grease gun, and it does not cause confusion; just remove the cap and you can monitor the grease level at any time. Specification: Item Type: Bearing Buddy Material: Stainless Steel Application: Fits on most trailers boat with 2.717 inch hub diameter. Package List: 2 x Bearing Buddy Note: Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.