A rectangular ND filter with a neutral ND32 (5 apertures) 4mm thickness size is 4 x 5.65 inches and can be used for various mat boxes etc. Made with high quality SCHOTT (Shot) B270 glass. The visible light transmittance is very high, and the ultra-precision polishing ensures high flatness accuracy on both sides. The coating on both sides is oil-proof, waterproof, and dust-proof, so you can quickly wipe the oil and dirt on your hands with a soft cloth to remove stress-free photography. In addition, it has excellent antistatic properties, and prevents dust and other adhesion.