Trijicon AC12035 Compact ACOG Quick Release Mount, Low, 1.5x16S, 1.5x24, 2x20, 3x24 & 3x30 Models, Black Fits: 1.5x16s (M16 base), 1.5x24, 2x20, 3x24 and 3x30 ACOG models Color: black Length: 2.10 inch