Wood Filled Wood filaments combine a PLA base material with cork, wood dust, or other derivatives, giving the models a real wooden look and feel. Metal Filled Metal filled filaments are made by mixing a fine metal powder into a base material, providing a unique metallic finish and added weight. Carbon Fiber Filled Carbon fiber filaments contain short fibers that are infused into a PLA or ABS base material to help increase strength and stiffness. PLA PLA is the go-to material for most users due to its ease-of-use, dimensional accuracy, and low cost. Flexible Flexible filaments, commonly referred to as TPE or TPU, are known for their elasticity allowing the material to easily stretch and bend.