Prothane Leaf Spring And Shackle Bushings Vehicles With A Leaf Spring And Shackle Set Up Lean Heavily On The Springs To Take The Shock Out Of A Bump. Not Only Does A Leaf Spring Reduce The Force Of A Bump That You Feel, But It Also Evenly Distributes The Load Across The Chassis Instead Of The Whole Load Pressing Down On One Point. Your Ability To Get To Point A To Point B Without Scraping The Pavement Is Heavily Dependent On The Leaf Spring And Shackle Bushings Which Mount The Spring To The Frame. Prothane's Polyurethane Is A Stronger Material For The Mounting Points Of A Leaf Spring And Shackle. Polyurethane Leaf Spring Bushings Are Able To Handle The Stress From The Suspension And Are Not Vulnerable To Road Grime. With Prothane's Polyurethane, You Can Protect Your Vehicle's Ability To Carry A Load, And Your Bumpy Free Ride, For Years To Come. Product Info: Prothane 64-73 Compatible With Fo-Rd Compatible With Mustang Rear Spring & 1/2In Shackle Bushings - One Set Will Cover The Left And Right Side Manufacturer Part Number: Part Number: 6-1051 Product Contents: 1 Of Super Grease - 19-1705-0012 Of Metal Sleeves - 60587 (3/4 X .120 X 3.110 Inches)4 Of Rear Spring Bushings - 604848 Of Shackle Bushings - 60485