Tiffen Black Pro-Mist 1 (BPM) 4" x 4" This is a standard Black Pro-Mist filter used in movies and commercials. Please refer to the photos for the condition. We will ship with a tracking number within 24 hours of purchase. The size is 4" x 4" and the thickness is 4mm, which is a common size for cinema filters. (4 inches per side = 101.6mm) Many matte boxes support both 4" x 5.65" and 4" x 4" filters (e.g., Smallrig, Bright Tangerine, Chrosziel). [Smallrig Compatibility] - Lightweight Matte Box 2660/3556: Standard support (up to 2 filters / 4 mm thick) Compatible with both 4 x 4" and 4 x 5.65" filters. - Mini Matte Box 3196: Compatible by adding the separately sold Filter Tray 4 x 4" (model number 3320) (Standard tray is only for 4 x 5.65" filters) - Mini Matte Box Lite 3575: Standard support (can accommodate both 4 x 4" and 4 x 5.65" filters)