Kodak 4 x 4" 87 Opaque Infrared Wratten 2 Gel Filter - This black infrared filter will filter out entire visible spectrum. It is used with black and white infrared films with a sensitivity up to approximately 1000nm. Filter factor is determined by the film sensitivity.
Most Kodak gelatin filters are available in 3 x 3" (75 x 75mm), 4 x 4" (100 x 100mm), 6 x 6" (150 x 150mm), 14 x 18" (350 x 450mm) and 4 x 12" (10.2 x 30.5mm).