At ESSI LASH, we produce all kinds of lashes curl of J/B/C/CC/D/DD/L/M/U/LC/LD.
Among all of the curls, J and B are loose curl, it is suitable for bottom lashes.
C/CC/D/DD are the common and popular curls. Especially C curl and D curl, they are the most most common and most popular.  CC is little more curly than CC, and DD is little more curly than D.
U curl is the tightest curl.
L curl is retangle curl.
M, LC and LD are all adjusted based on the U and L curl.