Mixed length tray 9mm-14mm. 16 rows per tray. C-Curls have a perkier, fresher curl. They can be mixed together to achieve all the specific goals you and client agree can be accomplished. Incorporating C-Curls can be daunting at first, if you've only been exposed to J-Curls. The big secret? Take care to match the base of the natural lash to the curvature of the base of the C-Curl. A natural lash that is flexible and in good condition (not brittle, etc.) is a desirable candidate for any extension.