This is the same rubber spacer supplied with AeroCatch hood pin latches. The 10.4mm (0.41") ID is sized to be an easy fit over the M10 threads on AeroCatch pins, but it will also fit 3/8" diameter pins.
You can trim the 40mm (1.575") length to fit your application. AeroCatch recommends sizing the bumper so that you must apply a little pressure to the panel in order to latch the pin. The consistent 20.5mm (0.81") OD means that if you cut it in half, you will end up with two equally usable 20mm long pieces.
One spacer required per pin. Sold individually.
Not used with AeroCatch 2 or AeroCatch 3.