Material: AS resin Feature:Eco-Friendly Capacity :2-4 servings Technics:v-shaped trapezoidal Filter holders have a curved, swirl design to improve coffee flow. Prevents water from simply standing in the coffee bed. This design produces clean cupping coffee and avoids bitterness that is associated with an over extracted brew. Large opening in base of filter aids in keeping flow at a proper rate. Filtercones are widely used by coffee professionals and aficionados.