New Energy Suspension coil spring isolator bushings.  These are the "ramped" design, meaning the lip where the coil spring sits gets thicker at one edge. These are black polyurethane, which is stronger than rubber and has less flex.  View photo #2 for the dimension appendix.  This set is 2 1/8" ID (2.125"/dimension A), 2 1/2" Lip diameter (2.50"/dimension B), 3 1/4" OD (3.25"/dimension C), 1/4" thinnest ramp (.25"/dimension D), 1" total height (1.0"/dimension F), 5/8" riser height (.625"/dimension H).  Sold as a pair (2 bushings).  Universal applications.