From the red color (I can't quite see the decal on your shock), it appears to be a Koni- not stock on a 'Goose but maybe better. Their American store on the East Coast stocks parts and bumper rubbers are cheap. Note front and rear shocks use different length rubbers and sometimes, different durometers. To install them, Koni's upper shock eye unscrews so the bumper rubber can be slipped on the shaft. It keeps your shock from metal-to-metal contact over big bumps, which can completely destroy a shock. They also have a service center for rebuilds but that is NOT cheap.