Glycosylation peak height.  Six dodecamers as individual trimers. N peak is counted full with each trimer.  Same MO as many previous posts: y axis is grayscale 0-255, this peak is almost always prominent, one either side of the N term peak and present on most SP-D dodecamers (exceptions being when glycosylation is not present). Check out value from the first four dodecamers, here.