Research a Taper FOS

http://materials.globalspec.com/SpecSearch/Suppliers/Materials_Chemicals_Adhesives/Composites_Textiles_Reinforcements/Foams_Foam_Materials?SrchItem=1&frmqry=fos#

Was 1st guest looking for a foam? To me 'taper FO' means a hard fibre optic taper block which changes the size of an image from the input to output faces. Perhaps he can expand on the question.