From Emerson & Cuming Microwave Products, Inc., ECCOSTOCK CK is a light-weight, low-loss dielectric material that can be custom-molded and machined to produce complex configurations. Dielectric constant can be dialed in from 1.7 to 15.0. This product is suited to aerospace applications due to its lightness. The material also lends itself to use in microwave lenses because of its low loss and its ability to be molded into large volume speheres without shrinking or cracking.