Curl (shape): C = natural curl, most popular for everyday sets. D = tighter, more dramatic curl. L/LC = flat base with lift, ideal for hooded or downturned eyes.
Thickness (diameter): Measured in mm — .15mm and .20mm are standard classic thicknesses. .03–.07mm are ultra-fine, used for volume fans (more lashes per fan without extra weight).
Length: Trays typically range from 8mm (shortest, inner corner) to 16mm (longest, outer corner) per strip.