Black polystyrene frame with double white core mats, V-groove and 3 openings. Top mat Black Bottom mat white Opening sizes Top 1.25 X 1.25 Medium 7.5 X 9.5 Bottom 1.75 X 5.25 Inshed size should be 12 X 16 VIEW TO We are starting a new project and will need much more frames (5000 to 10000) regularly. Thanks Frank