This Tiffen 4x4" #87 Infrared Filter is designed for black and white infrared films when you wish to transmit only the infrared spectrum without any part of the visible spectrum. Prior testing is recommended.nnnFeatures:nn- Type: Infraredn- Size: 4x4" (100 x 100 x 4mm)n- Grade: 87n- Filter Factor: Determined by film sensitivityn- Effect: No visible transmissionn- Application: For black and white infrared film onlyn- Construction: ColorCore glass