Recycled Polypropylene (PP #5) Pellets, Black, 1 kg One kilogram (2.2 pounds) of 100% recycled plastic resin pellets manufactured by Birch Plastics, repackaged for sale in retail quantities for desktop injection machines and home hobbyists, makers, and crafters. This plastic is polypropylene (PP), identified by the #5 recycling symbol. Large recyclers mix all different colors of raw material together and add black pigment to make it all homogeneous. It's great if you want black or don't care about color, since it costs a bit less than the "natural" pellets that can have colorant added. You can also mix in a small quantity of these to darken your own shredded plastic.