It has a convoluted shape similar to the Eccosorb CV material, but is made from a much more open cell foam material. This open structure allows the piece to be used at high humidity although long term exposure to water and UV should be avoided. For indoor higher power requirements, cooling air can be circulated through the foam structure, either by natural convection or by fan, to keep the temperature of the piece down. Because of the rounded convolutions and lack of sharp corners and tips, Eccosorb OCF is the preferred absorber for mm wave frequencies and for grazing incidence angles out to 60° off-normal. It s available in 2 thicknesses 7.5 cm ad 10 cm.