328 Dull Marine Blue is a skein of Appleton Crewel Wool, the finer 2-ply wool spun from pure British fleece. It is the classic thread for crewel and Jacobean embroidery: it follows fine detail closely and, with two or more lengths in the needle, gives fuller coverage, including needlepoint on fine canvas. Two different shades in the same needle let you mix your own tones.
Appleton colours are grouped into named ranges, within which the shades run from light to dark; the shade number is printed on the skein label. Below are the closest shades, useful for shading or for replacing a colour.