The Tiffen 4x5.65" Sepia 1 Filter is a rectangular filter with a clear color that provides a diffuser effect. It is designed to be used with cameras and has a drop-in mount fitting for easy installation. The filter size of 4x5.65 inches ensures a secure fit on most camera lenses, allowing photographers to enhance their images with a subtle sepia tone and diffused lighting effect. This filter is a versatile and high-quality accessory for photographers looking to add a unique touch to their work.