Delrin is a highly "slippery", hard wearing type of plastic(?) One of its uses is on the slider pucks for sport motorcycles to help keep the breakable bits off the ground in a crash. The idea is that the delrin "puck" slides across the ground, grinding down as you hopefully scrub off speed and come to a stop, and preventing the bike parts from hitting the ground and disintegrating, causing fluids all over the road, which multiplies the problem, or from a body part digging in and flipping the bike.
Strong stuff.
Don't forget the "rubber" hook gears on the newer vintages too. The ones that don't like oils of any kind, and sit right below the hook that you oil.