Rubber extrusion is a process where rubber is formed into desired profile shapes. It involves pushing rubber through a die. A die is a shaped opening. This leads to a continuous mass of rubber with a homogeneously shaped profile. Think of squeezing playdough through a mold. The shape of the mold dictates the final shape of the play dough. In this case, the “play dough” is rubber. This approach is useful for fabricating long items with narrow cross sections.