These are OEM and fit perfectly. I clamped the old bumper in a vise and used the handle as leverage to simply pull up and twist to remove. The installation required a little more effort. I had to carve a small bevel on the iron face of the hammer head and use some lube to thread the new bumpers onto the hammer head. Secure the piece of iron in a vise so you can use your body weight to assemble the bumpers.