3M Diamond Grade 983-21-48INX49IN ~ Conspicuity Markings 983-21 HC edge sealed Fluorescent Yellow (48 Inch x 49 Inch)3M Diamond Grade Conspicuity Markings, 983 21 HC, edge sealed, fluorescent yellow, 48 in x 49 in 3M Diamond Grade Conspicuity Markings 983 are microprismatic retroreflective conspicuity markings designed to mark the emergency exits, sides, and rear of vehicles for enhanced visibility and detection on the road These markings feature prismatic lens technology formed in a transparent, synthetic resin, engineered to provide good visibility even at wide