8-Line. Centration on the previously marked center and optical zone ring can be easily placed binocularly, reducing the parallax problems with higher profile markers. 4.0mm long radial lines. Inner diameter of blades is 4.5mm. Marks on top of ring assist with centration. Semi-sharp blades allow minimal marking pressure. Round, knurled handle with dull finish. Low profile stainless steel construction. Available in 4 lines, 8 lines, and 16 lines. Overall length: 80mm, 3.1 inches.